diff --git a/Cargo.lock b/Cargo.lock
index f63b5e72ad..9d4dfd29e7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -74,6 +74,7 @@ dependencies = [
  "boa_interner",
  "boa_profiler",
  "boa_unicode",
+ "cfg-if",
  "chrono",
  "criterion",
  "dyn-clone",
@@ -91,6 +92,7 @@ dependencies = [
  "num-bigint",
  "num-integer",
  "num-traits",
+ "num_enum",
  "once_cell",
  "rand",
  "regress",
@@ -98,6 +100,7 @@ dependencies = [
  "ryu-js",
  "serde",
  "serde_json",
+ "sptr",
  "sys-locale",
  "tap",
  "unicode-normalization",
@@ -992,6 +995,27 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "num_enum"
+version = "0.5.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf5395665662ef45796a4ff5486c5d41d29e0c09640af4c5f17fd94ee2c119c9"
+dependencies = [
+ "num_enum_derive",
+]
+
+[[package]]
+name = "num_enum_derive"
+version = "0.5.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b0498641e53dd6ac1a4f22547548caa6864cc4933784319cd1775271c5a46ce"
+dependencies = [
+ "proc-macro-crate",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.14.0"
@@ -1136,6 +1160,16 @@ version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
 
+[[package]]
+name = "proc-macro-crate"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e17d47ce914bf4de440332250b0edd23ce48c005f59fab39d3335866b114f11a"
+dependencies = [
+ "thiserror",
+ "toml",
+]
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -1459,6 +1493,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "sptr"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e0d4365121b91e8522958da77ce29c004333daeaf0711225c4727c8c5f49941"
+
 [[package]]
 name = "stable_deref_trait"
 version = "1.2.0"
@@ -1618,6 +1658,15 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cda74da7e1a664f795bb1f8a87ec406fb89a02522cf6e50620d016add6dbbf5c"
 
+[[package]]
+name = "toml"
+version = "0.5.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d82e1a7758622a465f8cee077614c73484dac5b836c02ff6a40d5d1010324d7"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "unicode-general-category"
 version = "0.5.1"
diff --git a/boa_cli/src/main.rs b/boa_cli/src/main.rs
index cd01b62990..fcb485267f 100644
--- a/boa_cli/src/main.rs
+++ b/boa_cli/src/main.rs
@@ -93,7 +93,7 @@ struct Opt {
     #[clap(long, short = 'a', value_name = "FORMAT", ignore_case = true, arg_enum)]
     dump_ast: Option<Option<DumpFormat>>,
 
-    /// Dump the AST to stdout with the given format.
+    /// Dump the compiled bytecode and trace the execution stack
     #[clap(long = "trace", short = 't')]
     trace: bool,
 
diff --git a/boa_engine/Cargo.toml b/boa_engine/Cargo.toml
index 3b4daab8ed..8de4200122 100644
--- a/boa_engine/Cargo.toml
+++ b/boa_engine/Cargo.toml
@@ -23,6 +23,7 @@ intl = [
     "dep:icu_testdata",
     "dep:sys-locale"
 ]
+nan_boxing = ["dep:sptr", "dep:num_enum"]
 
 # Enable Boa's WHATWG console object implementation.
 console = []
@@ -50,6 +51,9 @@ unicode-normalization = "0.1.21"
 dyn-clone = "1.0.9"
 once_cell = "1.14.0"
 tap = "1.0.1"
+cfg-if = "1.0.0"
+sptr = { version = "0.3.1", optional = true }
+num_enum = { version = "0.5.7", optional = true }
 icu_locale_canonicalizer = { version = "0.6.0", features = ["serde"], optional = true }
 icu_locid = { version = "0.6.0", features = ["serde"], optional = true }
 icu_datetime = { version = "0.6.0", features = ["serde"], optional = true }
diff --git a/boa_engine/src/bigint.rs b/boa_engine/src/bigint.rs
index b06b921ea3..02536a6b1c 100644
--- a/boa_engine/src/bigint.rs
+++ b/boa_engine/src/bigint.rs
@@ -1,10 +1,11 @@
 //! This module implements the JavaScript bigint primitive rust type.
 
-use crate::{builtins::Number, Context, JsValue};
+use crate::{builtins::Number, value::PointerType, Context, JsValue};
 use num_integer::Integer;
 use num_traits::{pow::Pow, FromPrimitive, One, ToPrimitive, Zero};
 use std::{
     fmt::{self, Display},
+    mem::{self, ManuallyDrop},
     ops::{Add, BitAnd, BitOr, BitXor, Div, Mul, Neg, Rem, Shl, Shr, Sub},
     rc::Rc,
 };
@@ -22,6 +23,16 @@ pub struct JsBigInt {
     inner: Rc<RawBigInt>,
 }
 
+unsafe impl PointerType for JsBigInt {
+    unsafe fn from_void_ptr(ptr: *mut ()) -> ManuallyDrop<Self> {
+        ManuallyDrop::new(mem::transmute(ptr))
+    }
+
+    unsafe fn into_void_ptr(bigint: ManuallyDrop<Self>) -> *mut () {
+        mem::transmute(bigint)
+    }
+}
+
 impl JsBigInt {
     /// Create a new [`JsBigInt`].
     #[inline]
diff --git a/boa_engine/src/builtins/array/array_iterator.rs b/boa_engine/src/builtins/array/array_iterator.rs
index 882a47c425..d1c6fefae7 100644
--- a/boa_engine/src/builtins/array/array_iterator.rs
+++ b/boa_engine/src/builtins/array/array_iterator.rs
@@ -68,7 +68,8 @@ impl ArrayIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%arrayiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let mut array_iterator = this.as_object().map(JsObject::borrow_mut);
+        let array_iterator = this.as_object();
+        let mut array_iterator = array_iterator.as_deref().map(JsObject::borrow_mut);
         let array_iterator = array_iterator
             .as_mut()
             .and_then(|obj| obj.as_array_iterator_mut())
diff --git a/boa_engine/src/builtins/array/mod.rs b/boa_engine/src/builtins/array/mod.rs
index 54f2280029..4887f3e2dd 100644
--- a/boa_engine/src/builtins/array/mod.rs
+++ b/boa_engine/src/builtins/array/mod.rs
@@ -29,7 +29,7 @@ use crate::{
     },
     property::{Attribute, PropertyDescriptor, PropertyNameKind},
     symbol::WellKnownSymbols,
-    value::{IntegerOrInfinity, JsValue},
+    value::{IntegerOrInfinity, JsValue, JsVariant},
     Context, JsResult, JsString,
 };
 use std::cmp::{max, min, Ordering};
@@ -374,7 +374,7 @@ impl Array {
         // 7. If IsConstructor(C) is false, throw a TypeError exception.
         if let Some(c) = c.as_constructor() {
             // 8. Return ? Construct(C, « 𝔽(length) »).
-            c.construct(&[JsValue::new(length)], Some(c), context)
+            c.construct(&[JsValue::new(length)], Some(&c), context)
         } else {
             context.throw_type_error("Symbol.species must be a constructor")
         }
@@ -404,9 +404,9 @@ impl Array {
         // 3. Else,
         //     a. If IsCallable(mapfn) is false, throw a TypeError exception.
         //     b. Let mapping be true.
-        let mapping = match mapfn {
-            JsValue::Undefined => None,
-            JsValue::Object(o) if o.is_callable() => Some(o),
+        let mapping = match mapfn.variant() {
+            JsVariant::Undefined => None,
+            JsVariant::Object(o) if o.is_callable() => Some(o),
             _ => return context.throw_type_error(format!("{} is not a function", mapfn.type_of())),
         };
 
@@ -423,7 +423,8 @@ impl Array {
             // b. Else,
             //     i. Let A be ? ArrayCreate(0en).
             let a = match this.as_constructor() {
-                Some(constructor) => constructor.construct(&[], None, context)?,
+                Some(constructor) => constructor
+                    .construct(&[], None, context)?,
                 _ => Self::array_create(0, None, context)?,
             };
 
@@ -455,9 +456,9 @@ impl Array {
                 let next_value = next.value(context)?;
 
                 // vi. If mapping is true, then
-                let mapped_value = if let Some(mapfn) = mapping {
+                let mapped_value = if let Some(ref mapfn) = mapping {
                     // 1. Let mappedValue be Call(mapfn, thisArg, « nextValue, 𝔽(k) »).
-                    let mapped_value = mapfn.call(this_arg, &[next_value, k.into()], context);
+                    let mapped_value = mapfn.call(&this_arg, &[next_value, k.into()], context);
 
                     // 2. IfAbruptCloseIterator(mappedValue, iteratorRecord).
                     if_abrupt_close_iterator!(mapped_value, iterator_record, context)
@@ -496,7 +497,8 @@ impl Array {
             // 10. Else,
             //     a. Let A be ? ArrayCreate(len).
             let a = match this.as_constructor() {
-                Some(constructor) => constructor.construct(&[len.into()], None, context)?,
+                Some(constructor) => constructor
+                    .construct(&[len.into()], None, context)?,
                 _ => Self::array_create(len, None, context)?,
             };
 
@@ -509,10 +511,10 @@ impl Array {
                 // b. Let kValue be ? Get(arrayLike, Pk).
                 let k_value = array_like.get(k, context)?;
 
-                let mapped_value = if let Some(mapfn) = mapping {
+                let mapped_value = if let Some(ref mapfn) = mapping {
                     // c. If mapping is true, then
                     //     i. Let mappedValue be ? Call(mapfn, thisArg, « kValue, 𝔽(k) »).
-                    mapfn.call(this_arg, &[k_value, k.into()], context)?
+                    mapfn.call(&this_arg, &[k_value, k.into()], context)?
                 } else {
                     // d. Else, let mappedValue be kValue.
                     k_value
@@ -572,7 +574,8 @@ impl Array {
         // 5. Else,
         //     a. Let A be ? ArrayCreate(len).
         let a = match this.as_constructor() {
-            Some(constructor) => constructor.construct(&[len.into()], None, context)?,
+            Some(constructor) => constructor
+                .construct(&[len.into()], None, context)?,
             _ => Self::array_create(len as u64, None, context)?,
         };
 
@@ -810,7 +813,8 @@ impl Array {
         // 2. Let len be ? LengthOfArrayLike(O).
         let len = o.length_of_array_like(context)?;
         // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let callback = args.get_or_undefined(0);
+        let callback = callback.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.forEach: invalid callback function")
         })?;
         // 4. Let k be 0.
@@ -826,7 +830,7 @@ impl Array {
                 let k_value = o.get(pk, context)?;
                 // ii. Perform ? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »).
                 let this_arg = args.get_or_undefined(1);
-                callback.call(this_arg, &[k_value, k.into(), o.clone().into()], context)?;
+                callback.call(&this_arg, &[k_value, k.into(), o.clone().into()], context)?;
             }
             // d. Set k to k + 1.
         }
@@ -1151,7 +1155,8 @@ impl Array {
         // 2. Let len be ? LengthOfArrayLike(O).
         let len = o.length_of_array_like(context)?;
         // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let callback = args.get_or_undefined(0);
+        let callback = callback.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.every: callback is not callable")
         })?;
 
@@ -1169,7 +1174,7 @@ impl Array {
                 let k_value = o.get(k, context)?;
                 // ii. Let testResult be ! ToBoolean(? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »)).
                 let test_result = callback
-                    .call(this_arg, &[k_value, k.into(), o.clone().into()], context)?
+                    .call(&this_arg, &[k_value, k.into(), o.clone().into()], context)?
                     .to_boolean();
                 // iii. If testResult is false, return false.
                 if !test_result {
@@ -1203,7 +1208,8 @@ impl Array {
         // 2. Let len be ? LengthOfArrayLike(O).
         let len = o.length_of_array_like(context)?;
         // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let callback = args.get_or_undefined(0);
+        let callback = callback.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.map: Callbackfn is not callable")
         })?;
 
@@ -1224,7 +1230,7 @@ impl Array {
                 let k_value = o.get(k, context)?;
                 // ii. Let mappedValue be ? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »).
                 let mapped_value =
-                    callback.call(this_arg, &[k_value, k.into(), this.into()], context)?;
+                    callback.call(&this_arg, &[k_value, k.into(), this.into()], context)?;
                 // iii. Perform ? CreateDataPropertyOrThrow(A, Pk, mappedValue).
                 a.create_data_property_or_throw(k, mapped_value, context)?;
             }
@@ -1376,7 +1382,7 @@ impl Array {
                 let element_k = o.get(k, context)?;
                 // ii. Let same be IsStrictlyEqual(searchElement, elementK).
                 // iii. If same is true, return 𝔽(k).
-                if JsValue::strict_equals(search_element, &element_k) {
+                if JsValue::strict_equals(&search_element, &element_k) {
                     return Ok(JsValue::new(k));
                 }
             }
@@ -1411,7 +1417,8 @@ impl Array {
         let len = o.length_of_array_like(context)?;
 
         // 3. If IsCallable(predicate) is false, throw a TypeError exception.
-        let predicate = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let predicate = args.get_or_undefined(0);
+        let predicate = predicate.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.find: predicate is not callable")
         })?;
 
@@ -1428,7 +1435,7 @@ impl Array {
             // c. Let testResult be ! ToBoolean(? Call(predicate, thisArg, « kValue, 𝔽(k), O »)).
             let test_result = predicate
                 .call(
-                    this_arg,
+                    &this_arg,
                     &[k_value.clone(), k.into(), o.clone().into()],
                     context,
                 )?
@@ -1468,7 +1475,8 @@ impl Array {
         let len = o.length_of_array_like(context)?;
 
         // 3. If IsCallable(predicate) is false, throw a TypeError exception.
-        let predicate = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let predicate = args.get_or_undefined(0);
+        let predicate = predicate.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.findIndex: predicate is not callable")
         })?;
 
@@ -1484,7 +1492,7 @@ impl Array {
             let k_value = o.get(pk, context)?;
             // c. Let testResult be ! ToBoolean(? Call(predicate, thisArg, « kValue, 𝔽(k), O »)).
             let test_result = predicate
-                .call(this_arg, &[k_value, k.into(), o.clone().into()], context)?
+                .call(&this_arg, &[k_value, k.into(), o.clone().into()], context)?
                 .to_boolean();
             // d. If testResult is true, return 𝔽(k).
             if test_result {
@@ -1519,7 +1527,8 @@ impl Array {
         let len = o.length_of_array_like(context)?;
 
         // 3. If IsCallable(predicate) is false, throw a TypeError exception.
-        let predicate = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let predicate = args.get_or_undefined(0);
+        let predicate = predicate.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.findLast: predicate is not callable")
         })?;
 
@@ -1534,7 +1543,7 @@ impl Array {
             // c. Let testResult be ! ToBoolean(? Call(predicate, thisArg, « kValue, 𝔽(k), O »)).
             let test_result = predicate
                 .call(
-                    this_arg,
+                    &this_arg,
                     &[k_value.clone(), k.into(), this.clone()],
                     context,
                 )?
@@ -1571,7 +1580,8 @@ impl Array {
         let len = o.length_of_array_like(context)?;
 
         // 3. If IsCallable(predicate) is false, throw a TypeError exception.
-        let predicate = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let predicate = args.get_or_undefined(0);
+        let predicate = predicate.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.findLastIndex: predicate is not callable")
         })?;
 
@@ -1585,7 +1595,7 @@ impl Array {
             let k_value = o.get(k, context)?;
             // c. Let testResult be ! ToBoolean(? Call(predicate, thisArg, « kValue, 𝔽(k), O »)).
             let test_result = predicate
-                .call(this_arg, &[k_value, k.into(), this.clone()], context)?
+                .call(&this_arg, &[k_value, k.into(), this.clone()], context)?
                 .to_boolean();
             // d. If testResult is true, return 𝔽(k).
             if test_result {
@@ -1676,7 +1686,8 @@ impl Array {
         let source_len = o.length_of_array_like(context)?;
 
         // 3. If ! IsCallable(mapperFunction) is false, throw a TypeError exception.
-        let mapper_function = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let mapper_function = args.get_or_undefined(0);
+        let mapper_function = mapper_function.as_callable().ok_or_else(|| {
             context.construct_type_error("flatMap mapper function is not callable")
         })?;
 
@@ -1690,8 +1701,8 @@ impl Array {
             source_len,
             0,
             1,
-            Some(mapper_function),
-            args.get_or_undefined(1),
+            Some(&mapper_function),
+            &args.get_or_undefined(1),
             context,
         )?;
 
@@ -1780,7 +1791,7 @@ impl Array {
                     // 4. Set targetIndex to ? FlattenIntoArray(target, element, elementLen, targetIndex, newDepth)
                     target_index = Self::flatten_into_array(
                         target,
-                        element,
+                        &element,
                         element_len,
                         target_index,
                         new_depth,
@@ -1924,7 +1935,7 @@ impl Array {
             // a. Let elementK be ? Get(O, ! ToString(𝔽(k))).
             let element_k = o.get(k, context)?;
             // b. If SameValueZero(searchElement, elementK) is true, return true.
-            if JsValue::same_value_zero(search_element, &element_k) {
+            if JsValue::same_value_zero(&search_element, &element_k) {
                 return Ok(JsValue::new(true));
             }
             // c. Set k to k + 1.
@@ -2205,7 +2216,8 @@ impl Array {
         let length = o.length_of_array_like(context)?;
 
         // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let callback = args.get_or_undefined(0);
+        let callback = callback.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.filter: `callback` must be callable")
         })?;
         let this_arg = args.get_or_undefined(1);
@@ -2228,7 +2240,7 @@ impl Array {
                 let args = [element.clone(), JsValue::new(idx), JsValue::new(o.clone())];
 
                 // ii. Let selected be ! ToBoolean(? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »)).
-                let selected = callback.call(this_arg, &args, context)?.to_boolean();
+                let selected = callback.call(&this_arg, &args, context)?.to_boolean();
 
                 // iii. If selected is true, then
                 if selected {
@@ -2269,7 +2281,8 @@ impl Array {
         // 2. Let len be ? LengthOfArrayLike(O).
         let len = o.length_of_array_like(context)?;
         // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let callback = args.get_or_undefined(0);
+        let callback = callback.as_callable().ok_or_else(|| {
             context.construct_type_error("Array.prototype.some: callback is not callable")
         })?;
 
@@ -2286,7 +2299,7 @@ impl Array {
                 // ii. Let testResult be ! ToBoolean(? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »)).
                 let this_arg = args.get_or_undefined(1);
                 let test_result = callback
-                    .call(this_arg, &[k_value, k.into(), o.clone().into()], context)?
+                    .call(&this_arg, &[k_value, k.into(), o.clone().into()], context)?
                     .to_boolean();
                 // iii. If testResult is true, return true.
                 if test_result {
@@ -2317,9 +2330,10 @@ impl Array {
         context: &mut Context,
     ) -> JsResult<JsValue> {
         // 1. If comparefn is not undefined and IsCallable(comparefn) is false, throw a TypeError exception.
-        let comparefn = match args.get_or_undefined(0) {
-            JsValue::Object(ref obj) if obj.is_callable() => Some(obj),
-            JsValue::Undefined => None,
+        let comparefn = args.get_or_undefined(0);
+        let comparefn = match comparefn.variant() {
+            JsVariant::Object(obj) if obj.is_callable() => Some(obj),
+            JsVariant::Undefined => None,
             _ => {
                 return context.throw_type_error(
                     "The comparison function must be either a function or undefined",
@@ -2346,11 +2360,11 @@ impl Array {
                 }
 
                 // 4. If comparefn is not undefined, then
-                if let Some(cmp) = comparefn {
+                if let Some(ref cmp) = comparefn {
                     let args = [x.clone(), y.clone()];
                     // a. Let v be ? ToNumber(? Call(comparefn, undefined, « x, y »)).
                     let v = cmp
-                        .call(&JsValue::Undefined, &args, context)?
+                        .call(&JsValue::undefined(), &args, context)?
                         .to_number(context)?;
                     // b. If v is NaN, return +0𝔽.
                     // c. Return v.
@@ -2454,7 +2468,8 @@ impl Array {
         let len = o.length_of_array_like(context)?;
 
         // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let callback = args.get_or_undefined(0);
+        let callback = callback.as_callable().ok_or_else(|| {
             context
                 .construct_type_error("Array.prototype.reduce: callback function is not callable")
         })?;
@@ -2549,7 +2564,8 @@ impl Array {
         let len = o.length_of_array_like(context)?;
 
         // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback = args.get_or_undefined(0).as_callable().ok_or_else(|| {
+        let callback = args.get_or_undefined(0);
+        let callback = callback.as_callable().ok_or_else(|| {
             context.construct_type_error(
                 "Array.prototype.reduceRight: callback function is not callable",
             )
diff --git a/boa_engine/src/builtins/array_buffer/mod.rs b/boa_engine/src/builtins/array_buffer/mod.rs
index 576bd53b2c..0d776367a0 100644
--- a/boa_engine/src/builtins/array_buffer/mod.rs
+++ b/boa_engine/src/builtins/array_buffer/mod.rs
@@ -262,7 +262,7 @@ impl ArrayBuffer {
         // 20. If SameValue(new, O) is true, throw a TypeError exception.
         if this
             .as_object()
-            .map(|obj| JsObject::equals(obj, &new))
+            .map(|obj| JsObject::equals(&obj, &new))
             .unwrap_or_default()
         {
             return context.throw_type_error("New ArrayBuffer is the same as this ArrayBuffer");
@@ -334,7 +334,7 @@ impl ArrayBuffer {
         obj.borrow_mut().data = ObjectData::array_buffer(Self {
             array_buffer_data: Some(block),
             array_buffer_byte_length: byte_length,
-            array_buffer_detach_key: JsValue::Undefined,
+            array_buffer_detach_key: JsValue::undefined(),
         });
 
         // 5. Return obj.
diff --git a/boa_engine/src/builtins/async_generator/mod.rs b/boa_engine/src/builtins/async_generator/mod.rs
index 021141007a..75a9aeb666 100644
--- a/boa_engine/src/builtins/async_generator/mod.rs
+++ b/boa_engine/src/builtins/async_generator/mod.rs
@@ -203,7 +203,7 @@ impl AsyncGenerator {
         }
 
         // 7. Let completion be NormalCompletion(value).
-        let completion = (Ok(args.get_or_undefined(0).clone()), false);
+        let completion = (Ok(args.get_or_undefined(0)), false);
 
         // 8. Perform AsyncGeneratorEnqueue(generator, completion, promiseCapability).
         generator.enqueue(completion.clone(), promise_capability.clone());
@@ -221,7 +221,7 @@ impl AsyncGenerator {
             drop(generator_obj_mut);
 
             Self::resume(
-                generator_object,
+                &generator_object,
                 state,
                 &generator_context,
                 completion,
@@ -272,7 +272,7 @@ impl AsyncGenerator {
         if_abrupt_reject_promise!(generator, promise_capability, context);
 
         // 5. Let completion be Completion Record { [[Type]]: return, [[Value]]: value, [[Target]]: empty }.
-        let completion = (Ok(args.get_or_undefined(0).clone()), true);
+        let completion = (Ok(args.get_or_undefined(0)), true);
 
         // 6. Perform AsyncGeneratorEnqueue(generator, completion, promiseCapability).
         generator.enqueue(completion.clone(), promise_capability.clone());
@@ -305,7 +305,7 @@ impl AsyncGenerator {
 
             drop(generator_obj_mut);
             Self::resume(
-                generator_object,
+                &generator_object,
                 state,
                 &generator_context,
                 completion,
@@ -376,7 +376,7 @@ impl AsyncGenerator {
                 .reject()
                 .call(
                     &JsValue::undefined(),
-                    &[args.get_or_undefined(0).clone()],
+                    &[args.get_or_undefined(0)],
                     context,
                 )
                 .expect("cannot fail per spec");
@@ -386,7 +386,7 @@ impl AsyncGenerator {
         }
 
         // 8. Let completion be ThrowCompletion(exception).
-        let completion = (Err(args.get_or_undefined(0).clone()), false);
+        let completion = (Err(args.get_or_undefined(0)), false);
 
         // 9. Perform AsyncGeneratorEnqueue(generator, completion, promiseCapability).
         generator.enqueue(completion.clone(), promise_capability.clone());
@@ -401,7 +401,7 @@ impl AsyncGenerator {
 
             // a. Perform AsyncGeneratorResume(generator, completion).
             Self::resume(
-                generator_object,
+                &generator_object,
                 state,
                 &generator_context,
                 completion,
@@ -622,7 +622,7 @@ impl AsyncGenerator {
                 gen.state = AsyncGeneratorState::Completed;
 
                 // b. Let result be NormalCompletion(value).
-                let result = Ok(args.get_or_undefined(0).clone());
+                let result = Ok(args.get_or_undefined(0));
 
                 // c. Perform AsyncGeneratorCompleteStep(generator, result, true).
                 let next = gen.queue.pop_front().expect("must have one entry");
@@ -655,7 +655,7 @@ impl AsyncGenerator {
                 gen.state = AsyncGeneratorState::Completed;
 
                 // b. Let result be ThrowCompletion(reason).
-                let result = Err(args.get_or_undefined(0).clone());
+                let result = Err(args.get_or_undefined(0));
 
                 // c. Perform AsyncGeneratorCompleteStep(generator, result, true).
                 let next = gen.queue.pop_front().expect("must have one entry");
diff --git a/boa_engine/src/builtins/bigint/mod.rs b/boa_engine/src/builtins/bigint/mod.rs
index dc1ddd3485..9225dd5325 100644
--- a/boa_engine/src/builtins/bigint/mod.rs
+++ b/boa_engine/src/builtins/bigint/mod.rs
@@ -133,6 +133,7 @@ impl BigInt {
         value
             // 1. If Type(value) is BigInt, return value.
             .as_bigint()
+            .as_deref()
             .cloned()
             // 2. If Type(value) is Object and value has a [[BigIntData]] internal slot, then
             //    a. Assert: Type(value.[[BigIntData]]) is BigInt.
diff --git a/boa_engine/src/builtins/boolean/tests.rs b/boa_engine/src/builtins/boolean/tests.rs
index 3d6ae4a3de..cc0e18ba0e 100644
--- a/boa_engine/src/builtins/boolean/tests.rs
+++ b/boa_engine/src/builtins/boolean/tests.rs
@@ -60,6 +60,6 @@ fn instances_have_correct_proto_set() {
 
     assert_eq!(
         &*bool_instance.as_object().unwrap().prototype(),
-        &bool_prototype.as_object().cloned()
+        &bool_prototype.as_object().as_deref().cloned()
     );
 }
diff --git a/boa_engine/src/builtins/console/mod.rs b/boa_engine/src/builtins/console/mod.rs
index dd2687c474..f73d407a2b 100644
--- a/boa_engine/src/builtins/console/mod.rs
+++ b/boa_engine/src/builtins/console/mod.rs
@@ -569,7 +569,7 @@ impl Console {
     #[allow(clippy::unnecessary_wraps)]
     pub(crate) fn dir(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         logger(
-            LogMessage::Info(display_obj(args.get_or_undefined(0), true)),
+            LogMessage::Info(display_obj(&args.get_or_undefined(0), true)),
             context.console(),
         );
         Ok(JsValue::undefined())
diff --git a/boa_engine/src/builtins/dataview/mod.rs b/boa_engine/src/builtins/dataview/mod.rs
index 0128d9c4bb..5b3f4d99c2 100644
--- a/boa_engine/src/builtins/dataview/mod.rs
+++ b/boa_engine/src/builtins/dataview/mod.rs
@@ -100,8 +100,8 @@ impl DataView {
     ) -> JsResult<JsValue> {
         let byte_length = args.get_or_undefined(2);
 
-        let buffer_obj = args
-            .get_or_undefined(0)
+        let buffer_obj = args.get_or_undefined(0);
+        let buffer_obj = buffer_obj
             .as_object()
             .ok_or_else(|| context.construct_type_error("buffer must be an ArrayBuffer"))?;
 
@@ -194,7 +194,8 @@ impl DataView {
     ) -> JsResult<JsValue> {
         // 1. Let O be the this value.
         // 2. Perform ? RequireInternalSlot(O, [[DataView]]).
-        let dataview = this.as_object().map(JsObject::borrow);
+        let dataview = this.as_object();
+        let dataview = dataview.as_deref().map(JsObject::borrow);
         let dataview = dataview
             .as_ref()
             .and_then(|obj| obj.as_data_view())
@@ -223,7 +224,8 @@ impl DataView {
     ) -> JsResult<JsValue> {
         // 1. Let O be the this value.
         // 2. Perform ? RequireInternalSlot(O, [[DataView]]).
-        let dataview = this.as_object().map(JsObject::borrow);
+        let dataview = this.as_object();
+        let dataview = dataview.as_deref().map(JsObject::borrow);
         let dataview = dataview
             .as_ref()
             .and_then(|obj| obj.as_data_view())
@@ -262,7 +264,8 @@ impl DataView {
     ) -> JsResult<JsValue> {
         // 1. Let O be the this value.
         // 2. Perform ? RequireInternalSlot(O, [[DataView]]).
-        let dataview = this.as_object().map(JsObject::borrow);
+        let dataview = this.as_object();
+        let dataview = dataview.as_deref().map(JsObject::borrow);
         let dataview = dataview
             .as_ref()
             .and_then(|obj| obj.as_data_view())
@@ -302,7 +305,8 @@ impl DataView {
     ) -> JsResult<JsValue> {
         // 1. Perform ? RequireInternalSlot(view, [[DataView]]).
         // 2. Assert: view has a [[ViewedArrayBuffer]] internal slot.
-        let view = view.as_object().map(JsObject::borrow);
+        let view = view.as_object();
+        let view = view.as_deref().map(JsObject::borrow);
         let view = view
             .as_ref()
             .and_then(|obj| obj.as_data_view())
@@ -373,8 +377,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::BigInt64,
             context,
         )
@@ -402,8 +406,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::BigUint64,
             context,
         )
@@ -431,8 +435,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Float32,
             context,
         )
@@ -460,8 +464,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Float64,
             context,
         )
@@ -489,8 +493,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Int8,
             context,
         )
@@ -518,8 +522,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Int16,
             context,
         )
@@ -547,8 +551,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Int32,
             context,
         )
@@ -576,8 +580,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Uint8,
             context,
         )
@@ -605,8 +609,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Uint16,
             context,
         )
@@ -634,8 +638,8 @@ impl DataView {
         // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
         Self::get_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Uint32,
             context,
         )
@@ -661,7 +665,8 @@ impl DataView {
     ) -> JsResult<JsValue> {
         // 1. Perform ? RequireInternalSlot(view, [[DataView]]).
         // 2. Assert: view has a [[ViewedArrayBuffer]] internal slot.
-        let view = view.as_object().map(JsObject::borrow);
+        let view = view.as_object();
+        let view = view.as_deref().map(JsObject::borrow);
         let view = view
             .as_ref()
             .and_then(|obj| obj.as_data_view())
@@ -742,10 +747,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, BigUint64, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::BigInt64,
-            value,
+            &value,
             context,
         )
     }
@@ -773,10 +778,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, BigUint64, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::BigUint64,
-            value,
+            &value,
             context,
         )
     }
@@ -804,10 +809,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Float32, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Float32,
-            value,
+            &value,
             context,
         )
     }
@@ -835,10 +840,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Float64, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Float64,
-            value,
+            &value,
             context,
         )
     }
@@ -866,10 +871,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Int8, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Int8,
-            value,
+            &value,
             context,
         )
     }
@@ -897,10 +902,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Int16, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Int16,
-            value,
+            &value,
             context,
         )
     }
@@ -928,10 +933,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Int32, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Int32,
-            value,
+            &value,
             context,
         )
     }
@@ -959,10 +964,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Uint8, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Uint8,
-            value,
+            &value,
             context,
         )
     }
@@ -990,10 +995,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Uint16, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Uint16,
-            value,
+            &value,
             context,
         )
     }
@@ -1021,10 +1026,10 @@ impl DataView {
         // 2. Return ? SetViewValue(v, byteOffset, littleEndian, Uint32, value).
         Self::set_view_value(
             this,
-            byte_offset,
-            is_little_endian,
+            &byte_offset,
+            &is_little_endian,
             TypedArrayKind::Uint32,
-            value,
+            &value,
             context,
         )
     }
diff --git a/boa_engine/src/builtins/date/mod.rs b/boa_engine/src/builtins/date/mod.rs
index 95fc226d9e..f46c28cf4a 100644
--- a/boa_engine/src/builtins/date/mod.rs
+++ b/boa_engine/src/builtins/date/mod.rs
@@ -9,7 +9,7 @@ use crate::{
         internal_methods::get_prototype_from_constructor, ConstructorBuilder, JsObject, ObjectData,
     },
     symbol::WellKnownSymbols,
-    value::{JsValue, PreferredType},
+    value::{JsValue, JsVariant, PreferredType},
     Context, JsResult, JsString,
 };
 use boa_profiler::Profiler;
@@ -390,24 +390,25 @@ impl Date {
         context: &mut Context,
     ) -> JsResult<JsObject> {
         let value = &args[0];
-        let tv = match this_time_value(value, context) {
-            Ok(dt) => dt.0,
-            _ => match value.to_primitive(context, PreferredType::Default)? {
-                JsValue::String(ref str) => match chrono::DateTime::parse_from_rfc3339(str) {
+        let tv = if let Ok(dt) = this_time_value(value, context) {
+            dt.0
+        } else {
+            let tv = value.to_primitive(context, PreferredType::Default)?;
+            if let JsVariant::String(ref str) = tv.variant() {
+                match chrono::DateTime::parse_from_rfc3339(str) {
                     Ok(dt) => Some(dt.naive_utc()),
                     _ => None,
-                },
-                tv => {
-                    let tv = tv.to_number(context)?;
-                    if tv.is_nan() {
-                        None
-                    } else {
-                        let secs = (tv / 1_000f64) as i64;
-                        let nano_secs = ((tv % 1_000f64) * 1_000_000f64) as u32;
-                        NaiveDateTime::from_timestamp_opt(secs, nano_secs)
-                    }
                 }
-            },
+            } else {
+                let tv = tv.to_number(context)?;
+                if tv.is_nan() {
+                    None
+                } else {
+                    let secs = (tv / 1_000f64) as i64;
+                    let nano_secs = ((tv % 1_000f64) * 1_000_000f64) as u32;
+                    NaiveDateTime::from_timestamp_opt(secs, nano_secs)
+                }
+            }
         };
 
         let tv = tv.filter(|time| Self::time_clip(time.timestamp_millis() as f64).is_some());
@@ -512,7 +513,7 @@ impl Date {
 
         let hint = args.get_or_undefined(0);
 
-        let try_first = match hint.as_string().map(JsString::as_str) {
+        let try_first = match hint.as_string().as_deref().map(JsString::as_str) {
             // 3. If hint is "string" or "default", then
             // a. Let tryFirst be string.
             Some("string" | "default") => PreferredType::String,
@@ -1848,7 +1849,7 @@ impl Date {
 
         match DateTime::parse_from_rfc3339(&args[0].to_string(context)?) {
             Ok(v) => Ok(JsValue::new(v.naive_utc().timestamp_millis() as f64)),
-            _ => Ok(JsValue::new(f64::NAN)),
+            _ => Ok(JsValue::nan()),
         }
     }
 
diff --git a/boa_engine/src/builtins/date/tests.rs b/boa_engine/src/builtins/date/tests.rs
index 057fd576fd..7918cae085 100644
--- a/boa_engine/src/builtins/date/tests.rs
+++ b/boa_engine/src/builtins/date/tests.rs
@@ -13,7 +13,7 @@ fn forward_dt_utc(context: &mut Context, src: &str) -> Option<NaiveDateTime> {
         panic!("expected success")
     };
 
-    if let JsValue::Object(ref date_time) = date_time {
+    if let Some(date_time) = date_time.as_object() {
         if let Some(date_time) = date_time.borrow().as_date() {
             date_time.0
         } else {
diff --git a/boa_engine/src/builtins/error/aggregate.rs b/boa_engine/src/builtins/error/aggregate.rs
index 5c384177c1..42ccb98c94 100644
--- a/boa_engine/src/builtins/error/aggregate.rs
+++ b/boa_engine/src/builtins/error/aggregate.rs
@@ -86,11 +86,11 @@ impl AggregateError {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Error::install_error_cause(&o, args.get_or_undefined(2), context)?;
+        Error::install_error_cause(&o, &args.get_or_undefined(2), context)?;
 
         // 5. Let errorsList be ? IterableToList(errors).
         let errors = args.get_or_undefined(0);
-        let errors_list = iterable_to_list(context, errors, None)?;
+        let errors_list = iterable_to_list(context, &errors, None)?;
         // 6. Perform ! DefinePropertyOrThrow(O, "errors",
         //    PropertyDescriptor {
         //      [[Configurable]]: true,
diff --git a/boa_engine/src/builtins/error/eval.rs b/boa_engine/src/builtins/error/eval.rs
index 563749207c..c99a0e70ff 100644
--- a/boa_engine/src/builtins/error/eval.rs
+++ b/boa_engine/src/builtins/error/eval.rs
@@ -83,7 +83,7 @@ impl EvalError {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Error::install_error_cause(&o, args.get_or_undefined(1), context)?;
+        Error::install_error_cause(&o, &args.get_or_undefined(1), context)?;
 
         // 5. Return O.
         Ok(o.into())
diff --git a/boa_engine/src/builtins/error/mod.rs b/boa_engine/src/builtins/error/mod.rs
index c68d185444..30312aa9a5 100644
--- a/boa_engine/src/builtins/error/mod.rs
+++ b/boa_engine/src/builtins/error/mod.rs
@@ -120,7 +120,7 @@ impl Error {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Self::install_error_cause(&o, args.get_or_undefined(1), context)?;
+        Self::install_error_cause(&o, &args.get_or_undefined(1), context)?;
 
         // 5. Return O.
         Ok(o.into())
diff --git a/boa_engine/src/builtins/error/range.rs b/boa_engine/src/builtins/error/range.rs
index 1fa1258b0a..675fffe34d 100644
--- a/boa_engine/src/builtins/error/range.rs
+++ b/boa_engine/src/builtins/error/range.rs
@@ -81,7 +81,7 @@ impl RangeError {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Error::install_error_cause(&o, args.get_or_undefined(1), context)?;
+        Error::install_error_cause(&o, &args.get_or_undefined(1), context)?;
 
         // 5. Return O.
         Ok(o.into())
diff --git a/boa_engine/src/builtins/error/reference.rs b/boa_engine/src/builtins/error/reference.rs
index e130678b95..8353d23cb6 100644
--- a/boa_engine/src/builtins/error/reference.rs
+++ b/boa_engine/src/builtins/error/reference.rs
@@ -87,7 +87,7 @@ impl ReferenceError {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Error::install_error_cause(&o, args.get_or_undefined(1), context)?;
+        Error::install_error_cause(&o, &args.get_or_undefined(1), context)?;
 
         // 5. Return O.
         Ok(o.into())
diff --git a/boa_engine/src/builtins/error/syntax.rs b/boa_engine/src/builtins/error/syntax.rs
index c7dfb012d3..c017f1654b 100644
--- a/boa_engine/src/builtins/error/syntax.rs
+++ b/boa_engine/src/builtins/error/syntax.rs
@@ -86,7 +86,7 @@ impl SyntaxError {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Error::install_error_cause(&o, args.get_or_undefined(1), context)?;
+        Error::install_error_cause(&o, &args.get_or_undefined(1), context)?;
 
         // 5. Return O.
         Ok(o.into())
diff --git a/boa_engine/src/builtins/error/type.rs b/boa_engine/src/builtins/error/type.rs
index 1f39077784..604b5c75ec 100644
--- a/boa_engine/src/builtins/error/type.rs
+++ b/boa_engine/src/builtins/error/type.rs
@@ -87,7 +87,7 @@ impl TypeError {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Error::install_error_cause(&o, args.get_or_undefined(1), context)?;
+        Error::install_error_cause(&o, &args.get_or_undefined(1), context)?;
 
         // 5. Return O.
         Ok(o.into())
diff --git a/boa_engine/src/builtins/error/uri.rs b/boa_engine/src/builtins/error/uri.rs
index 21469f338d..04fa7a5ffd 100644
--- a/boa_engine/src/builtins/error/uri.rs
+++ b/boa_engine/src/builtins/error/uri.rs
@@ -82,7 +82,7 @@ impl UriError {
         }
 
         // 4. Perform ? InstallErrorCause(O, options).
-        Error::install_error_cause(&o, args.get_or_undefined(1), context)?;
+        Error::install_error_cause(&o, &args.get_or_undefined(1), context)?;
 
         // 5. Return O.
         Ok(o.into())
diff --git a/boa_engine/src/builtins/eval/mod.rs b/boa_engine/src/builtins/eval/mod.rs
index 71b82951fa..8938f2ecf2 100644
--- a/boa_engine/src/builtins/eval/mod.rs
+++ b/boa_engine/src/builtins/eval/mod.rs
@@ -50,7 +50,7 @@ impl Eval {
     /// [spec]: https://tc39.es/ecma262/#sec-eval-x
     fn eval(_: &JsValue, args: &[JsValue], context: &mut Context) -> Result<JsValue, JsValue> {
         // 1. Return ? PerformEval(x, false, false).
-        Self::perform_eval(args.get_or_undefined(0), false, false, context)
+        Self::perform_eval(&args.get_or_undefined(0), false, false, context)
     }
 
     /// `19.2.1.1 PerformEval ( x, strictCaller, direct )`
diff --git a/boa_engine/src/builtins/function/arguments.rs b/boa_engine/src/builtins/function/arguments.rs
index ab1626a87c..a8a8c2e3e0 100644
--- a/boa_engine/src/builtins/function/arguments.rs
+++ b/boa_engine/src/builtins/function/arguments.rs
@@ -196,7 +196,6 @@ impl Arguments {
         // In the case of duplicate parameter names, the last one is bound as the environment binding.
         //
         // The following logic implements the steps 17-19 adjusted for our environment structure.
-
         let mut bindings = FxHashMap::default();
         let mut property_index = 0;
         'outer: for formal in formals.parameters.iter() {
diff --git a/boa_engine/src/builtins/function/mod.rs b/boa_engine/src/builtins/function/mod.rs
index d5c23ea1bc..a93ec0b4ea 100644
--- a/boa_engine/src/builtins/function/mod.rs
+++ b/boa_engine/src/builtins/function/mod.rs
@@ -682,7 +682,7 @@ impl BuiltInFunctionObject {
             // TODO?: 3.a. PrepareForTailCall
 
             // b. Return ? Call(func, thisArg).
-            return func.call(this_arg, &[], context);
+            return func.call(&this_arg, &[], context);
         }
 
         // 4. Let argList be ? CreateListFromArrayLike(argArray).
@@ -692,7 +692,7 @@ impl BuiltInFunctionObject {
         // TODO?: 5. PrepareForTailCall
 
         // 6. Return ? Call(func, thisArg, argList).
-        func.call(this_arg, &arg_list, context)
+        func.call(&this_arg, &arg_list, context)
     }
 
     /// `Function.prototype.bind ( thisArg, ...args )`
@@ -714,7 +714,7 @@ impl BuiltInFunctionObject {
             context.construct_type_error("cannot bind `this` without a `[[Call]]` internal method")
         })?;
 
-        let this_arg = args.get_or_undefined(0).clone();
+        let this_arg = args.get_or_undefined(0);
         let bound_args = args.get(1..).unwrap_or(&[]).to_vec();
         let arg_count = bound_args.len() as i64;
 
@@ -769,7 +769,9 @@ impl BuiltInFunctionObject {
         // 9. If Type(targetName) is not String, set targetName to the empty String.
         let target_name = target_name
             .as_string()
-            .map_or(JsString::new(""), Clone::clone);
+            .as_deref()
+            .cloned()
+            .unwrap_or_default();
 
         // 10. Perform SetFunctionName(F, targetName, "bound").
         set_function_name(&f, &target_name.into(), Some("bound"), context);
@@ -800,12 +802,13 @@ impl BuiltInFunctionObject {
         // TODO?: 3. Perform PrepareForTailCall
 
         // 4. Return ? Call(func, thisArg, args).
-        func.call(this_arg, args.get(1..).unwrap_or(&[]), context)
+        func.call(&this_arg, args.get(1..).unwrap_or(&[]), context)
     }
 
     #[allow(clippy::wrong_self_convention)]
     fn to_string(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let object = this.as_object().map(JsObject::borrow);
+        let object = this.as_object();
+        let object = object.as_deref().map(JsObject::borrow);
         let function = object
             .as_deref()
             .and_then(Object::as_function)
@@ -855,7 +858,7 @@ impl BuiltInFunctionObject {
     fn has_instance(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let F be the this value.
         // 2. Return ? OrdinaryHasInstance(F, V).
-        Ok(JsValue::ordinary_has_instance(this, args.get_or_undefined(0), context)?.into())
+        Ok(JsValue::ordinary_has_instance(this, &args.get_or_undefined(0), context)?.into())
     }
 
     #[allow(clippy::unnecessary_wraps)]
diff --git a/boa_engine/src/builtins/function/tests.rs b/boa_engine/src/builtins/function/tests.rs
index f183343973..eaa9d6cc5e 100644
--- a/boa_engine/src/builtins/function/tests.rs
+++ b/boa_engine/src/builtins/function/tests.rs
@@ -129,7 +129,7 @@ fn function_prototype_call() {
         "#;
     let value = forward_val(&mut context, func).unwrap();
     assert!(value.is_string());
-    assert_eq!(value.as_string().unwrap(), "[object Error]");
+    assert_eq!(*value.as_string().unwrap(), "[object Error]");
 }
 
 #[test]
@@ -246,7 +246,7 @@ fn closure_capture_clone() {
                 object
                     .__get_own_property__(&"key".into(), context)?
                     .and_then(|prop| prop.value().cloned())
-                    .and_then(|val| val.as_string().cloned())
+                    .and_then(|val| val.as_string().as_deref().cloned())
                     .ok_or_else(|| context.construct_type_error("invalid `key` property"))?,
             );
             Ok(hw.into())
diff --git a/boa_engine/src/builtins/generator/mod.rs b/boa_engine/src/builtins/generator/mod.rs
index c446078500..0fbf0a1523 100644
--- a/boa_engine/src/builtins/generator/mod.rs
+++ b/boa_engine/src/builtins/generator/mod.rs
@@ -148,8 +148,8 @@ impl Generator {
     ) -> JsResult<JsValue> {
         // 1. Return ? GeneratorResume(this value, value, empty).
         match this.as_object() {
-            Some(obj) if obj.is_generator() => {
-                Self::generator_resume(obj, args.get_or_undefined(0), context)
+            Some(ref obj) if obj.is_generator() => {
+                Self::generator_resume(obj, &args.get_or_undefined(0), context)
             }
             _ => context.throw_type_error("Generator.prototype.next called on non generator"),
         }
@@ -173,7 +173,7 @@ impl Generator {
         // 1. Let g be the this value.
         // 2. Let C be Completion { [[Type]]: return, [[Value]]: value, [[Target]]: empty }.
         // 3. Return ? GeneratorResumeAbrupt(g, C, empty).
-        Self::generator_resume_abrupt(this, Ok(args.get_or_undefined(0).clone()), context)
+        Self::generator_resume_abrupt(this, Ok(args.get_or_undefined(0)), context)
     }
 
     /// `Generator.prototype.throw ( exception )`
@@ -195,7 +195,7 @@ impl Generator {
         // 1. Let g be the this value.
         // 2. Let C be ThrowCompletion(exception).
         // 3. Return ? GeneratorResumeAbrupt(g, C, empty).
-        Self::generator_resume_abrupt(this, Err(args.get_or_undefined(0).clone()), context)
+        Self::generator_resume_abrupt(this, Err(args.get_or_undefined(0)), context)
     }
 
     /// `27.5.3.3 GeneratorResume ( generator, value, generatorBrand )`
diff --git a/boa_engine/src/builtins/intl/mod.rs b/boa_engine/src/builtins/intl/mod.rs
index 116dbfbe70..6ab7613819 100644
--- a/boa_engine/src/builtins/intl/mod.rs
+++ b/boa_engine/src/builtins/intl/mod.rs
@@ -77,7 +77,7 @@ impl Intl {
         let ll = canonicalize_locale_list(args, context)?;
 
         // 2. Return CreateArrayFromList(ll).
-        Ok(JsValue::Object(Array::create_array_from_list(
+        Ok(JsValue::new(Array::create_array_from_list(
             ll.into_iter().map(|loc| loc.to_string().into()),
             context,
         )))
@@ -595,7 +595,7 @@ fn resolve_locale(
         // e. Let value be keyLocaleData[0].
         // TODO f. Assert: Type(value) is either String or Null.
         let mut value = match key_locale_data.get(0) {
-            Some(first_elt) => JsValue::String(first_elt.clone()),
+            Some(first_elt) => JsValue::from(first_elt.clone()),
             None => JsValue::null(),
         };
 
@@ -616,7 +616,7 @@ fn resolve_locale(
                     // a. If keyLocaleData contains requestedValue, then
                     if key_locale_data.contains(requested_value) {
                         // i. Let value be requestedValue.
-                        value = JsValue::String(JsString::new(requested_value));
+                        value = JsValue::from(JsString::new(requested_value));
                         // ii. Let supportedExtensionAddition be the string-concatenation
                         // of "-", key, "-", and value.
                         supported_extension_addition =
@@ -625,7 +625,7 @@ fn resolve_locale(
                 // 4. Else if keyLocaleData contains "true", then
                 } else if key_locale_data.contains(&JsString::new("true")) {
                     // a. Let value be "true".
-                    value = JsValue::String(JsString::new("true"));
+                    value = JsValue::from(JsString::new("true"));
                     // b. Let supportedExtensionAddition be the string-concatenation of "-" and key.
                     supported_extension_addition = JsString::concat_array(&["-", key]);
                 }
@@ -659,7 +659,7 @@ fn resolve_locale(
                 if let Some(options_val_str) = options_value.as_string() {
                     if options_val_str.is_empty() {
                         // a. Let optionsValue be "true".
-                        options_value = JsValue::String(JsString::new("true"));
+                        options_value = JsValue::from(JsString::new("true"));
                     }
                 }
             }
@@ -747,13 +747,13 @@ pub(crate) fn get_option(
     // 7. If values is not undefined and values does not contain an element equal to value,
     // throw a RangeError exception.
     value = match r#type {
-        GetOptionType::Boolean => JsValue::Boolean(value.to_boolean()),
+        GetOptionType::Boolean => JsValue::from(value.to_boolean()),
         GetOptionType::String => {
             let string_value = value.to_string(context)?;
             if !values.is_empty() && !values.contains(&string_value) {
                 return context.throw_range_error("GetOption: values array does not contain value");
             }
-            JsValue::String(string_value)
+            JsValue::from(string_value)
         }
     };
 
diff --git a/boa_engine/src/builtins/intl/tests.rs b/boa_engine/src/builtins/intl/tests.rs
index 6abfb0c600..75fcf7940f 100644
--- a/boa_engine/src/builtins/intl/tests.rs
+++ b/boa_engine/src/builtins/intl/tests.rs
@@ -284,7 +284,7 @@ fn get_opt() {
     let mut context = Context::default();
 
     let values = Vec::<JsString>::new();
-    let fallback = JsValue::String(JsString::new("fallback"));
+    let fallback = JsValue::from(JsString::new("fallback"));
     let options_obj = JsObject::empty();
     let option_type = GetOptionType::String;
     let get_option_result = get_option(
@@ -299,9 +299,9 @@ fn get_opt() {
     assert_eq!(get_option_result, fallback);
 
     let values = Vec::<JsString>::new();
-    let fallback = JsValue::String(JsString::new("fallback"));
+    let fallback = JsValue::from(JsString::new("fallback"));
     let options_obj = JsObject::empty();
-    let locale_value = JsValue::String(JsString::new("en-US"));
+    let locale_value = JsValue::from(JsString::new("en-US"));
     options_obj
         .set("Locale", locale_value.clone(), true, &mut context)
         .expect("Setting a property should not fail");
@@ -317,10 +317,10 @@ fn get_opt() {
     .expect("GetOption should not fail on string test");
     assert_eq!(get_option_result, locale_value);
 
-    let fallback = JsValue::String(JsString::new("fallback"));
+    let fallback = JsValue::from(JsString::new("fallback"));
     let options_obj = JsObject::empty();
     let locale_string = JsString::new("en-US");
-    let locale_value = JsValue::String(locale_string.clone());
+    let locale_value = JsValue::from(locale_string.clone());
     let values = vec![locale_string];
     options_obj
         .set("Locale", locale_value.clone(), true, &mut context)
@@ -356,9 +356,9 @@ fn get_opt() {
     .expect("GetOption should not fail on boolean test");
     assert_eq!(get_option_result, boolean_value);
 
-    let fallback = JsValue::String(JsString::new("fallback"));
+    let fallback = JsValue::from(JsString::new("fallback"));
     let options_obj = JsObject::empty();
-    let locale_value = JsValue::String(JsString::new("en-US"));
+    let locale_value = JsValue::from(JsString::new("en-US"));
     let other_locale_str = JsString::new("de-DE");
     let values = vec![other_locale_str];
     options_obj
@@ -473,7 +473,7 @@ fn to_date_time_opts() {
     )
     .expect("toDateTimeOptions should not fail in date test");
 
-    let numeric_jsstring = JsValue::String(JsString::new("numeric"));
+    let numeric_jsstring = JsValue::from(JsString::new("numeric"));
     assert_eq!(
         date_time_opts.get("year", &mut context),
         Ok(numeric_jsstring.clone())
@@ -495,7 +495,7 @@ fn to_date_time_opts() {
     )
     .expect("toDateTimeOptions should not fail in time test");
 
-    let numeric_jsstring = JsValue::String(JsString::new("numeric"));
+    let numeric_jsstring = JsValue::from(JsString::new("numeric"));
     assert_eq!(
         date_time_opts.get("hour", &mut context),
         Ok(numeric_jsstring.clone())
@@ -517,7 +517,7 @@ fn to_date_time_opts() {
     )
     .expect("toDateTimeOptions should not fail when testing required = 'any'");
 
-    let numeric_jsstring = JsValue::String(JsString::new("numeric"));
+    let numeric_jsstring = JsValue::from(JsString::new("numeric"));
     assert_eq!(
         date_time_opts.get("year", &mut context),
         Ok(numeric_jsstring.clone())
diff --git a/boa_engine/src/builtins/iterable/mod.rs b/boa_engine/src/builtins/iterable/mod.rs
index 78bbfc97f4..de38df46de 100644
--- a/boa_engine/src/builtins/iterable/mod.rs
+++ b/boa_engine/src/builtins/iterable/mod.rs
@@ -153,7 +153,7 @@ impl JsValue {
                     // 1. Let syncMethod be ? GetMethod(obj, @@iterator).
                     let sync_method = self
                         .get_method(WellKnownSymbols::iterator(), context)?
-                        .map_or(Self::Undefined, Self::from);
+                        .map_or(Self::undefined(), Self::from);
                     // 2. Let syncIteratorRecord be ? GetIterator(obj, sync, syncMethod).
                     let _sync_iterator_record =
                         self.get_iterator(context, Some(IteratorHint::Sync), Some(sync_method));
@@ -163,7 +163,7 @@ impl JsValue {
             } else {
                 // b. Otherwise, set method to ? GetMethod(obj, @@iterator).
                 self.get_method(WellKnownSymbols::iterator(), context)?
-                    .map_or(Self::Undefined, Self::from)
+                    .map_or(Self::undefined(), Self::from)
             }
         };
 
diff --git a/boa_engine/src/builtins/json/mod.rs b/boa_engine/src/builtins/json/mod.rs
index e51e10110c..3653bdd899 100644
--- a/boa_engine/src/builtins/json/mod.rs
+++ b/boa_engine/src/builtins/json/mod.rs
@@ -95,7 +95,7 @@ impl Json {
         let unfiltered = context.eval(script_string.as_bytes())?;
 
         // 11. If IsCallable(reviver) is true, then
-        if let Some(obj) = args.get_or_undefined(1).as_callable() {
+        if let Some(ref obj) = args.get_or_undefined(1).as_callable() {
             // a. Let root be ! OrdinaryObjectCreate(%Object.prototype%).
             let root = context.construct_object();
 
@@ -129,7 +129,7 @@ impl Json {
         let val = holder.get(name.clone(), context)?;
 
         // 2. If Type(val) is Object, then
-        if let Some(obj) = val.as_object() {
+        if let Some(ref obj) = val.as_object() {
             // a. Let isArray be ? IsArray(val).
             // b. If isArray is true, then
             if obj.is_array_abstract(context)? {
@@ -280,7 +280,7 @@ impl Json {
             }
         }
 
-        let mut space = args.get_or_undefined(2).clone();
+        let mut space = args.get_or_undefined(2);
 
         // 5. If Type(space) is Object, then
         if let Some(space_obj) = space.as_object() {
@@ -332,7 +332,7 @@ impl Json {
 
         // 10. Perform ! CreateDataPropertyOrThrow(wrapper, the empty String, value).
         wrapper
-            .create_data_property_or_throw("", args.get_or_undefined(0).clone(), context)
+            .create_data_property_or_throw("", args.get_or_undefined(0), context)
             .expect("CreateDataPropertyOrThrow should never fail here");
 
         // 11. Let state be the Record { [[ReplacerFunction]]: ReplacerFunction, [[Stack]]: stack, [[Indent]]: indent, [[Gap]]: gap, [[PropertyList]]: PropertyList }.
@@ -388,7 +388,7 @@ impl Json {
         }
 
         // 4. If Type(value) is Object, then
-        if let Some(obj) = value.as_object().cloned() {
+        if let Some(obj) = value.as_object().as_deref().cloned() {
             // a. If value has a [[NumberData]] internal slot, then
             if obj.is_number() {
                 // i. Set value to ? ToNumber(value).
@@ -427,7 +427,7 @@ impl Json {
         }
 
         // 8. If Type(value) is String, return QuoteJSONString(value).
-        if let Some(s) = value.as_string() {
+        if let Some(ref s) = value.as_string() {
             return Ok(Some(Self::quote_json_string(s)));
         }
 
@@ -452,7 +452,7 @@ impl Json {
         }
 
         // 11. If Type(value) is Object and IsCallable(value) is false, then
-        if let Some(obj) = value.as_object() {
+        if let Some(ref obj) = value.as_object() {
             if !obj.is_callable() {
                 // a. Let isArray be ? IsArray(value).
                 // b. If isArray is true, return ? SerializeJSONArray(state, value).
diff --git a/boa_engine/src/builtins/map/map_iterator.rs b/boa_engine/src/builtins/map/map_iterator.rs
index 80cc1697ce..f1877a627b 100644
--- a/boa_engine/src/builtins/map/map_iterator.rs
+++ b/boa_engine/src/builtins/map/map_iterator.rs
@@ -72,7 +72,8 @@ impl MapIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%mapiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let mut map_iterator = this.as_object().map(JsObject::borrow_mut);
+        let map_iterator = this.as_object();
+        let mut map_iterator = map_iterator.as_deref().map(JsObject::borrow_mut);
         let map_iterator = map_iterator
             .as_mut()
             .and_then(|obj| obj.as_map_iterator_mut())
diff --git a/boa_engine/src/builtins/map/mod.rs b/boa_engine/src/builtins/map/mod.rs
index 8e8920744b..d2db963e64 100644
--- a/boa_engine/src/builtins/map/mod.rs
+++ b/boa_engine/src/builtins/map/mod.rs
@@ -21,6 +21,7 @@ use crate::{
     },
     property::{Attribute, PropertyNameKind},
     symbol::WellKnownSymbols,
+    value::JsVariant,
     Context, JsResult, JsValue,
 };
 use boa_profiler::Profiler;
@@ -141,7 +142,7 @@ impl Map {
         let adder = map.get("set", context)?;
 
         // 6. Return ? AddEntriesFromIterable(map, iterable, adder).
-        add_entries_from_iterable(&map, iterable, &adder, context)
+        add_entries_from_iterable(&map, &iterable, &adder, context)
     }
 
     /// `get Map [ @@species ]`
@@ -219,11 +220,11 @@ impl Map {
             // 2. Perform ? RequireInternalSlot(M, [[MapData]]).
             // 3. Let entries be the List that is M.[[MapData]].
             if let Some(map) = object.borrow_mut().as_map_mut() {
-                let key = match key {
-                    JsValue::Rational(r) => {
+                let key = match key.variant() {
+                    JsVariant::Float64(r) => {
                         // 5. If key is -0𝔽, set key to +0𝔽.
                         if r.is_zero() {
-                            JsValue::Rational(0f64)
+                            JsValue::new(0f64)
                         } else {
                             key.clone()
                         }
@@ -235,7 +236,7 @@ impl Map {
                 // i. Set p.[[Value]] to value.
                 // 6. Let p be the Record { [[Key]]: key, [[Value]]: value }.
                 // 7. Append p as the last element of entries.
-                map.insert(key, value.clone());
+                map.insert(key, value);
                 // ii. Return M.
                 // 8. Return M.
                 return Ok(this.clone());
@@ -303,7 +304,7 @@ impl Map {
                 // ii. Set p.[[Value]] to empty.
                 // iii. Return true.
                 // 5. Return false.
-                return Ok(map.remove(key).is_some().into());
+                return Ok(map.remove(&key).is_some().into());
             }
         }
         context.throw_type_error("'this' is not a Map")
@@ -324,29 +325,21 @@ impl Map {
         args: &[JsValue],
         context: &mut Context,
     ) -> JsResult<JsValue> {
-        const JS_ZERO: &JsValue = &JsValue::Rational(0f64);
-
         let key = args.get_or_undefined(0);
-        let key = match key {
-            JsValue::Rational(r) => {
-                if r.is_zero() {
-                    JS_ZERO
-                } else {
-                    key
-                }
-            }
-            _ => key,
+        let key = match key.variant() {
+            JsVariant::Float64(r) if r.is_zero() => JsValue::new(0f64),
+            _ => key.clone(),
         };
 
         // 1. Let M be the this value.
-        if let JsValue::Object(ref object) = this {
+        if let Some(object) = this.as_object() {
             // 2. Perform ? RequireInternalSlot(M, [[MapData]]).
             // 3. Let entries be the List that is M.[[MapData]].
             if let Some(map) = object.borrow().as_map_ref() {
                 // 4. For each Record { [[Key]], [[Value]] } p of entries, do
                 // a. If p.[[Key]] is not empty and SameValueZero(p.[[Key]], key) is true, return p.[[Value]].
                 // 5. Return undefined.
-                return Ok(map.get(key).cloned().unwrap_or_default());
+                return Ok(map.get(&key).cloned().unwrap_or_default());
             }
         }
 
@@ -396,29 +389,21 @@ impl Map {
         args: &[JsValue],
         context: &mut Context,
     ) -> JsResult<JsValue> {
-        const JS_ZERO: &JsValue = &JsValue::Rational(0f64);
-
         let key = args.get_or_undefined(0);
-        let key = match key {
-            JsValue::Rational(r) => {
-                if r.is_zero() {
-                    JS_ZERO
-                } else {
-                    key
-                }
-            }
-            _ => key,
+        let key = match key.variant() {
+            JsVariant::Float64(r) if r.is_zero() => JsValue::new(0f64),
+            _ => key.clone(),
         };
 
         // 1. Let M be the this value.
-        if let JsValue::Object(ref object) = this {
+        if let Some(object) = this.as_object() {
             // 2. Perform ? RequireInternalSlot(M, [[MapData]]).
             // 3. Let entries be the List that is M.[[MapData]].
             if let Some(map) = object.borrow().as_map_ref() {
                 // 4. For each Record { [[Key]], [[Value]] } p of entries, do
                 // a. If p.[[Key]] is not empty and SameValueZero(p.[[Key]], key) is true, return true.
                 // 5. Return false.
-                return Ok(map.contains_key(key).into());
+                return Ok(map.contains_key(&key).into());
             }
         }
 
@@ -489,7 +474,7 @@ impl Map {
             // a. If e.[[Key]] is not empty, then
             if let Some(arguments) = arguments {
                 // i. Perform ? Call(callbackfn, thisArg, « e.[[Value]], e.[[Key]], M »).
-                callback.call(this_arg, &arguments, context)?;
+                callback.call(&this_arg, &arguments, context)?;
             }
 
             index += 1;
diff --git a/boa_engine/src/builtins/mod.rs b/boa_engine/src/builtins/mod.rs
index 89d8f32fed..e8e55f4316 100644
--- a/boa_engine/src/builtins/mod.rs
+++ b/boa_engine/src/builtins/mod.rs
@@ -211,16 +211,11 @@ pub trait JsArgs {
     /// Call this if you are thinking of calling something similar to
     /// `args.get(n).cloned().unwrap_or_default()` or
     /// `args.get(n).unwrap_or(&undefined)`.
-    ///
-    /// This returns a reference for efficiency, in case
-    /// you only need to call methods of `JsValue`, so
-    /// try to minimize calling `clone`.
-    fn get_or_undefined(&self, index: usize) -> &JsValue;
+    fn get_or_undefined(&self, index: usize) -> JsValue;
 }
 
 impl JsArgs for [JsValue] {
-    fn get_or_undefined(&self, index: usize) -> &JsValue {
-        const UNDEFINED: &JsValue = &JsValue::Undefined;
-        self.get(index).unwrap_or(UNDEFINED)
+    fn get_or_undefined(&self, index: usize) -> JsValue {
+        self.get(index).cloned().unwrap_or_else(JsValue::undefined)
     }
 }
diff --git a/boa_engine/src/builtins/number/mod.rs b/boa_engine/src/builtins/number/mod.rs
index e39ade669c..b32b896486 100644
--- a/boa_engine/src/builtins/number/mod.rs
+++ b/boa_engine/src/builtins/number/mod.rs
@@ -21,7 +21,7 @@ use crate::{
         JsObject, ObjectData,
     },
     property::Attribute,
-    value::{AbstractRelation, IntegerOrInfinity, JsValue},
+    value::{AbstractRelation, IntegerOrInfinity, JsValue, JsVariant},
     Context, JsResult,
 };
 use boa_profiler::Profiler;
@@ -220,7 +220,8 @@ impl Number {
         // 1. Let x be ? thisNumberValue(this value).
         let this_num = Self::this_number_value(this, context)?;
         let precision = match args.get(0) {
-            None | Some(JsValue::Undefined) => None,
+            None => None,
+            Some(n) if n.is_undefined() => None,
             // 2. Let f be ? ToIntegerOrInfinity(fractionDigits).
             Some(n) => Some(n.to_integer_or_infinity(context)?),
         };
@@ -992,9 +993,9 @@ impl Number {
         _ctx: &mut Context,
     ) -> JsResult<JsValue> {
         Ok(JsValue::new(if let Some(val) = args.get(0) {
-            match val {
-                JsValue::Integer(_) => true,
-                JsValue::Rational(number) => number.is_finite(),
+            match val.variant() {
+                JsVariant::Float64(number) => number.is_finite(),
+                JsVariant::Integer32(_) => true,
                 _ => false,
             }
         } else {
@@ -1041,13 +1042,7 @@ impl Number {
         args: &[JsValue],
         _ctx: &mut Context,
     ) -> JsResult<JsValue> {
-        Ok(JsValue::new(
-            if let Some(&JsValue::Rational(number)) = args.get(0) {
-                number.is_nan()
-            } else {
-                false
-            },
-        ))
+        Ok(JsValue::new(args.get(0).map_or(false, JsValue::is_nan)))
     }
 
     /// `Number.isSafeInteger( number )`
@@ -1070,9 +1065,9 @@ impl Number {
         args: &[JsValue],
         _ctx: &mut Context,
     ) -> JsResult<JsValue> {
-        Ok(JsValue::new(match args.get(0) {
-            Some(JsValue::Integer(_)) => true,
-            Some(JsValue::Rational(number)) if Self::is_float_integer(*number) => {
+        Ok(JsValue::new(match args.get(0).map(JsValue::variant) {
+            Some(JsVariant::Integer32(_)) => true,
+            Some(JsVariant::Float64(number)) if Self::is_float_integer(number) => {
                 number.abs() <= Self::MAX_SAFE_INTEGER
             }
             _ => false,
@@ -1087,9 +1082,9 @@ impl Number {
     /// [spec]: https://tc39.es/ecma262/#sec-isinteger
     #[inline]
     pub(crate) fn is_integer(val: &JsValue) -> bool {
-        match val {
-            JsValue::Integer(_) => true,
-            JsValue::Rational(number) => Self::is_float_integer(*number),
+        match val.variant() {
+            JsVariant::Integer32(_) => true,
+            JsVariant::Float64(number) => Self::is_float_integer(number),
             _ => false,
         }
     }
diff --git a/boa_engine/src/builtins/object/for_in_iterator.rs b/boa_engine/src/builtins/object/for_in_iterator.rs
index 612daa0b49..4b1d366a61 100644
--- a/boa_engine/src/builtins/object/for_in_iterator.rs
+++ b/boa_engine/src/builtins/object/for_in_iterator.rs
@@ -67,7 +67,8 @@ impl ForInIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%foriniteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let mut iterator = this.as_object().map(JsObject::borrow_mut);
+        let iterator = this.as_object();
+        let mut iterator = iterator.as_deref().map(JsObject::borrow_mut);
         let iterator = iterator
             .as_mut()
             .and_then(|obj| obj.as_for_in_iterator_mut())
diff --git a/boa_engine/src/builtins/object/mod.rs b/boa_engine/src/builtins/object/mod.rs
index 891360ded7..a641fdb145 100644
--- a/boa_engine/src/builtins/object/mod.rs
+++ b/boa_engine/src/builtins/object/mod.rs
@@ -23,7 +23,7 @@ use crate::{
     },
     property::{Attribute, PropertyDescriptor, PropertyKey, PropertyNameKind},
     symbol::WellKnownSymbols,
-    value::JsValue,
+    value::{JsValue, JsVariant},
     Context, JsResult, JsString,
 };
 use boa_profiler::Profiler;
@@ -155,7 +155,7 @@ impl Object {
         // 2. Return ? O.[[GetPrototypeOf]]().
         let proto = obj.__get_prototype_of__(context)?;
 
-        Ok(proto.map_or(JsValue::Null, JsValue::new))
+        Ok(proto.map_or(JsValue::null(), JsValue::new))
     }
 
     /// `set Object.prototype.__proto__`
@@ -178,16 +178,17 @@ impl Object {
         let this = this.require_object_coercible(context)?;
 
         // 2. If Type(proto) is neither Object nor Null, return undefined.
-        let proto = match args.get_or_undefined(0) {
-            JsValue::Object(proto) => Some(proto.clone()),
-            JsValue::Null => None,
+        let proto = match args.get_or_undefined(0).variant() {
+            JsVariant::Object(proto) => Some(proto.clone()),
+            JsVariant::Null => None,
             _ => return Ok(JsValue::undefined()),
         };
 
         // 3. If Type(O) is not Object, return undefined.
-        let object = match this {
-            JsValue::Object(object) => object,
-            _ => return Ok(JsValue::undefined()),
+        let object = if let Some(o) = this.as_object() {
+            o
+        } else {
+            return Ok(JsValue::undefined());
         };
 
         // 4. Let status be ? O.[[SetPrototypeOf]](proto).
@@ -389,9 +390,9 @@ impl Object {
         let prototype = args.get_or_undefined(0);
         let properties = args.get_or_undefined(1);
 
-        let obj = match prototype {
-            JsValue::Object(_) | JsValue::Null => JsObject::from_proto_and_data(
-                prototype.as_object().cloned(),
+        let obj = match prototype.variant() {
+            JsVariant::Object(_) | JsVariant::Null => JsObject::from_proto_and_data(
+                prototype.as_object().as_deref().cloned(),
                 ObjectData::ordinary(),
             ),
             _ => {
@@ -403,7 +404,7 @@ impl Object {
         };
 
         if !properties.is_undefined() {
-            object_define_properties(&obj, properties, context)?;
+            object_define_properties(&obj, &properties, context)?;
             return Ok(obj.into());
         }
 
@@ -480,7 +481,7 @@ impl Object {
         }
 
         // 5. Return descriptors.
-        Ok(descriptors.into())
+        Ok(JsValue::new(descriptors))
     }
 
     /// The abstract operation `FromPropertyDescriptor`.
@@ -553,7 +554,7 @@ impl Object {
         let x = args.get_or_undefined(0);
         let y = args.get_or_undefined(1);
 
-        Ok(JsValue::same_value(x, y).into())
+        Ok(JsValue::same_value(&x, &y).into())
     }
 
     /// Get the `prototype` of an object.
@@ -574,7 +575,7 @@ impl Object {
         // 2. Return ? obj.[[GetPrototypeOf]]().
         Ok(obj
             .__get_prototype_of__(ctx)?
-            .map_or(JsValue::Null, JsValue::new))
+            .map_or(JsValue::null(), JsValue::new))
     }
 
     /// Set the `prototype` of an object.
@@ -582,9 +583,13 @@ impl Object {
     /// [More information][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-object.setprototypeof
-    pub fn set_prototype_of(_: &JsValue, args: &[JsValue], ctx: &mut Context) -> JsResult<JsValue> {
+    pub fn set_prototype_of(
+        _: &JsValue,
+        args: &[JsValue],
+        context: &mut Context,
+    ) -> JsResult<JsValue> {
         if args.len() < 2 {
-            return ctx.throw_type_error(format!(
+            return context.throw_type_error(format!(
                 "Object.setPrototypeOf: At least 2 arguments required, but only {} passed",
                 args.len()
             ));
@@ -595,16 +600,19 @@ impl Object {
             .get(0)
             .cloned()
             .unwrap_or_default()
-            .require_object_coercible(ctx)?
+            .require_object_coercible(context)?
             .clone();
 
-        let proto = match args.get_or_undefined(1) {
-            JsValue::Object(obj) => Some(obj.clone()),
-            JsValue::Null => None,
+        let proto = args.get_or_undefined(1);
+        let proto = match proto.variant() {
+            JsVariant::Object(obj) => Some(obj.clone()),
+            JsVariant::Null => None,
             // 2. If Type(proto) is neither Object nor Null, throw a TypeError exception.
-            val => {
-                return ctx
-                    .throw_type_error(format!("expected an object or null, got {}", val.type_of()))
+            _ => {
+                return context.throw_type_error(format!(
+                    "expected an object or null, got {}",
+                    proto.type_of()
+                ))
             }
         };
 
@@ -616,11 +624,11 @@ impl Object {
         };
 
         // 4. Let status be ? O.[[SetPrototypeOf]](proto).
-        let status = obj.__set_prototype_of__(proto, ctx)?;
+        let status = obj.__set_prototype_of__(proto, context)?;
 
         // 5. If status is false, throw a TypeError exception.
         if !status {
-            return ctx.throw_type_error("can't set prototype of this object");
+            return context.throw_type_error("can't set prototype of this object");
         }
 
         // 6. Return O.
@@ -646,7 +654,7 @@ impl Object {
         if !v.is_object() {
             return Ok(JsValue::new(false));
         }
-        let mut v = v.clone();
+        let mut v = v;
         let o = JsValue::new(this.to_object(context)?);
         loop {
             v = Self::get_prototype_of(this, &[v], context)?;
@@ -666,14 +674,14 @@ impl Object {
         context: &mut Context,
     ) -> JsResult<JsValue> {
         let object = args.get_or_undefined(0);
-        if let JsValue::Object(object) = object {
+        if let Some(object) = object.as_object() {
             let key = args
                 .get(1)
-                .unwrap_or(&JsValue::Undefined)
+                .unwrap_or(&JsValue::undefined())
                 .to_property_key(context)?;
             let desc = args
                 .get(2)
-                .unwrap_or(&JsValue::Undefined)
+                .unwrap_or(&JsValue::undefined())
                 .to_property_descriptor(context)?;
 
             object.define_property_or_throw(key, desc, context)?;
@@ -700,9 +708,9 @@ impl Object {
         context: &mut Context,
     ) -> JsResult<JsValue> {
         let arg = args.get_or_undefined(0);
-        if let JsValue::Object(obj) = arg {
+        if let Some(ref obj) = arg.as_object() {
             let props = args.get_or_undefined(1);
-            object_define_properties(obj, props, context)?;
+            object_define_properties(obj, &props, context)?;
             Ok(arg.clone())
         } else {
             context.throw_type_error("Expected an object")
@@ -778,7 +786,8 @@ impl Object {
         let tag = o.get(WellKnownSymbols::to_string_tag(), context)?;
 
         // 16. If Type(tag) is not String, set tag to builtinTag.
-        let tag_str = tag.as_string().map_or(builtin_tag, JsString::as_str);
+        let tag_str = tag.as_string();
+        let tag_str = tag_str.as_deref().map_or(builtin_tag, JsString::as_str);
 
         // 17. Return the string-concatenation of "[object ", tag, and "]".
         Ok(format!("[object {tag_str}]").into())
@@ -1152,7 +1161,7 @@ impl Object {
     ) -> JsResult<JsValue> {
         // 1. Return ? GetOwnPropertyKeys(O, string).
         let o = args.get_or_undefined(0);
-        get_own_property_keys(o, PropertyKeyType::String, context)
+        get_own_property_keys(&o, PropertyKeyType::String, context)
     }
 
     /// `Object.getOwnPropertySymbols( object )`
@@ -1170,7 +1179,7 @@ impl Object {
     ) -> JsResult<JsValue> {
         // 1. Return ? GetOwnPropertyKeys(O, symbol).
         let o = args.get_or_undefined(0);
-        get_own_property_keys(o, PropertyKeyType::Symbol, context)
+        get_own_property_keys(&o, PropertyKeyType::Symbol, context)
     }
 
     /// `Object.hasOwn( object, property )`
@@ -1202,7 +1211,8 @@ impl Object {
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/fromEntries
     pub fn from_entries(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Perform ? RequireObjectCoercible(iterable).
-        let iterable = args.get_or_undefined(0).require_object_coercible(context)?;
+        let iterable = args.get_or_undefined(0);
+        let iterable = iterable.require_object_coercible(context)?;
 
         // 2. Let obj be ! OrdinaryObjectCreate(%Object.prototype%).
         // 3. Assert: obj is an extensible ordinary object with no own properties.
diff --git a/boa_engine/src/builtins/promise/mod.rs b/boa_engine/src/builtins/promise/mod.rs
index 42189781a6..2350054365 100644
--- a/boa_engine/src/builtins/promise/mod.rs
+++ b/boa_engine/src/builtins/promise/mod.rs
@@ -144,13 +144,13 @@ impl PromiseCapability {
                         let reject = args.get_or_undefined(1);
 
                         // c. Set promiseCapability.[[Resolve]] to resolve.
-                        promise_capability.resolve = resolve.clone();
+                        promise_capability.resolve = resolve;
 
                         // d. Set promiseCapability.[[Reject]] to reject.
-                        promise_capability.reject = reject.clone();
+                        promise_capability.reject = reject;
 
                         // e. Return undefined.
-                        Ok(JsValue::Undefined)
+                        Ok(JsValue::undefined())
                     },
                     promise_capability.clone(),
                 )
@@ -170,6 +170,7 @@ impl PromiseCapability {
                 // 7. If IsCallable(promiseCapability.[[Resolve]]) is false, throw a TypeError exception.
                 let resolve = resolve
                     .as_object()
+                    .as_deref()
                     .cloned()
                     .and_then(JsFunction::from_object)
                     .ok_or_else(|| {
@@ -180,6 +181,7 @@ impl PromiseCapability {
                 // 8. If IsCallable(promiseCapability.[[Reject]]) is false, throw a TypeError exception.
                 let reject = reject
                     .as_object()
+                    .as_deref()
                     .cloned()
                     .and_then(JsFunction::from_object)
                     .ok_or_else(|| {
@@ -318,8 +320,8 @@ impl Promise {
 
         // 9. Let completion Completion(Call(executor, undefined, « resolvingFunctions.[[Resolve]], resolvingFunctions.[[Reject]] »)be ).
         let completion = context.call(
-            executor,
-            &JsValue::Undefined,
+            &executor,
+            &JsValue::undefined(),
             &[
                 resolving_functions.resolve,
                 resolving_functions.reject.clone(),
@@ -329,7 +331,7 @@ impl Promise {
         // 10. If completion is an abrupt completion, then
         if let Err(value) = completion {
             // a. Perform ? Call(resolvingFunctions.[[Reject]], undefined, « completion.[[Value]] »).
-            context.call(&resolving_functions.reject, &JsValue::Undefined, &[value])?;
+            context.call(&resolving_functions.reject, &JsValue::undefined(), &[value])?;
         }
 
         // 11. Return promise.
@@ -359,7 +361,7 @@ impl Promise {
         let c = c.as_object().expect("must be a constructor");
 
         // 3. Let promiseResolve be Completion(GetPromiseResolve(C)).
-        let promise_resolve = Self::get_promise_resolve(c, context);
+        let promise_resolve = Self::get_promise_resolve(&c, context);
 
         // 4. IfAbruptRejectPromise(promiseResolve, promiseCapability).
         if_abrupt_reject_promise!(promise_resolve, promise_capability, context);
@@ -374,7 +376,7 @@ impl Promise {
         // 7. Let result be Completion(PerformPromiseAll(iteratorRecord, C, promiseCapability, promiseResolve)).
         let mut result = Self::perform_promise_all(
             &mut iterator_record,
-            c,
+            &c,
             &promise_capability,
             &promise_resolve,
             context,
@@ -489,7 +491,7 @@ impl Promise {
             };
 
             // h. Append undefined to values.
-            values.borrow_mut().push(JsValue::Undefined);
+            values.borrow_mut().push(JsValue::undefined());
 
             // i. Let nextPromise be ? Call(promiseResolve, constructor, « nextValue »).
             let next_promise =
@@ -523,7 +525,7 @@ impl Promise {
                     // 7. Let remainingElementsCount be F.[[RemainingElements]].
 
                     // 8. Set values[index] to x.
-                    captures.values.borrow_mut()[captures.index] = args.get_or_undefined(0).clone();
+                    captures.values.borrow_mut()[captures.index] = args.get_or_undefined(0);
 
                     // 9. Set remainingElementsCount.[[Value]] to remainingElementsCount.[[Value]] - 1.
                     captures
@@ -600,7 +602,7 @@ impl Promise {
         let c = c.as_object().expect("must be a constructor");
 
         // 3. Let promiseResolve be Completion(GetPromiseResolve(C)).
-        let promise_resolve = Self::get_promise_resolve(c, context);
+        let promise_resolve = Self::get_promise_resolve(&c, context);
 
         // 4. IfAbruptRejectPromise(promiseResolve, promiseCapability).
         if_abrupt_reject_promise!(promise_resolve, promise_capability, context);
@@ -615,7 +617,7 @@ impl Promise {
         // 7. Let result be Completion(PerformPromiseAllSettled(iteratorRecord, C, promiseCapability, promiseResolve)).
         let mut result = Self::perform_promise_all_settled(
             &mut iterator_record,
-            c,
+            &c,
             &promise_capability,
             &promise_resolve,
             context,
@@ -931,7 +933,7 @@ impl Promise {
         let c = c.as_object().expect("must be a constructor");
 
         // 3. Let promiseResolve be Completion(GetPromiseResolve(C)).
-        let promise_resolve = Self::get_promise_resolve(c, context);
+        let promise_resolve = Self::get_promise_resolve(&c, context);
 
         // 4. IfAbruptRejectPromise(promiseResolve, promiseCapability).
         if_abrupt_reject_promise!(promise_resolve, promise_capability, context);
@@ -946,7 +948,7 @@ impl Promise {
         // 7. Let result be Completion(PerformPromiseAny(iteratorRecord, C, promiseCapability, promiseResolve)).
         let mut result = Self::perform_promise_any(
             &mut iterator_record,
-            c,
+            &c,
             &promise_capability,
             &promise_resolve,
             context,
@@ -1112,7 +1114,7 @@ impl Promise {
                     // 7. Let remainingElementsCount be F.[[RemainingElements]].
 
                     // 8. Set errors[index] to x.
-                    captures.errors.borrow_mut()[captures.index] = args.get_or_undefined(0).clone();
+                    captures.errors.borrow_mut()[captures.index] = args.get_or_undefined(0);
 
                     // 9. Set remainingElementsCount.[[Value]] to remainingElementsCount.[[Value]] - 1.
                     captures
@@ -1232,7 +1234,7 @@ impl Promise {
 
                 // 5. If alreadyResolved.[[Value]] is true, return undefined.
                 if already_resolved.get() {
-                    return Ok(JsValue::Undefined);
+                    return Ok(JsValue::undefined());
                 }
 
                 // 6. Set alreadyResolved.[[Value]] to true.
@@ -1241,7 +1243,7 @@ impl Promise {
                 let resolution = args.get_or_undefined(0);
 
                 // 7. If SameValue(resolution, promise) is true, then
-                if JsValue::same_value(resolution, &promise.clone().into()) {
+                if JsValue::same_value(&resolution, &promise.clone().into()) {
                     //   a. Let selfResolutionError be a newly created TypeError object.
                     let self_resolution_error =
                         context.construct_type_error("SameValue(resolution, promise) is true");
@@ -1254,7 +1256,7 @@ impl Promise {
                         .reject_promise(&self_resolution_error, context);
 
                     //   c. Return undefined.
-                    return Ok(JsValue::Undefined);
+                    return Ok(JsValue::undefined());
                 }
 
                 let then = if let Some(resolution) = resolution.as_object() {
@@ -1267,10 +1269,10 @@ impl Promise {
                         .borrow_mut()
                         .as_promise_mut()
                         .expect("Expected promise to be a Promise")
-                        .fulfill_promise(resolution, context)?;
+                        .fulfill_promise(&resolution, context)?;
 
                     //   b. Return undefined.
-                    return Ok(JsValue::Undefined);
+                    return Ok(JsValue::undefined());
                 };
 
                 let then_action = match then {
@@ -1284,7 +1286,7 @@ impl Promise {
                             .reject_promise(&value, context);
 
                         //   b. Return undefined.
-                        return Ok(JsValue::Undefined);
+                        return Ok(JsValue::undefined());
                     }
                     // 11. Let thenAction be then.[[Value]].
                     Ok(then) => then,
@@ -1299,10 +1301,10 @@ impl Promise {
                             .borrow_mut()
                             .as_promise_mut()
                             .expect("Expected promise to be a Promise")
-                            .fulfill_promise(resolution, context)?;
+                            .fulfill_promise(&resolution, context)?;
 
                         //   b. Return undefined.
-                        return Ok(JsValue::Undefined);
+                        return Ok(JsValue::undefined());
                     }
                 };
 
@@ -1321,7 +1323,7 @@ impl Promise {
                 context.host_enqueue_promise_job(job);
 
                 // 16. Return undefined.
-                Ok(JsValue::Undefined)
+                Ok(JsValue::undefined())
             },
             resolve_captures,
         )
@@ -1356,7 +1358,7 @@ impl Promise {
 
                 // 5. If alreadyResolved.[[Value]] is true, return undefined.
                 if already_resolved.get() {
-                    return Ok(JsValue::Undefined);
+                    return Ok(JsValue::undefined());
                 }
 
                 // 6. Set alreadyResolved.[[Value]] to true.
@@ -1368,10 +1370,10 @@ impl Promise {
                     .borrow_mut()
                     .as_promise_mut()
                     .expect("Expected promise to be a Promise")
-                    .reject_promise(args.get_or_undefined(0), context);
+                    .reject_promise(&args.get_or_undefined(0), context);
 
                 // 8. Return undefined.
-                Ok(JsValue::Undefined)
+                Ok(JsValue::undefined())
             },
             reject_captures,
         )
@@ -1523,7 +1525,7 @@ impl Promise {
 
         // 3. Let promiseResolve be Completion(GetPromiseResolve(C)).
         let promise_resolve =
-            Self::get_promise_resolve(c.as_object().expect("this was not an object"), context);
+            Self::get_promise_resolve(&c.as_object().expect("this was not an object"), context);
 
         // 4. IfAbruptRejectPromise(promiseResolve, promiseCapability).
         if_abrupt_reject_promise!(promise_resolve, promise_capability, context);
@@ -1648,7 +1650,7 @@ impl Promise {
         context.call(
             &promise_capability.reject.clone().into(),
             &JsValue::undefined(),
-            &[r.clone()],
+            &[r],
         )?;
 
         // 4. Return promiseCapability.[[Promise]].
@@ -1671,7 +1673,7 @@ impl Promise {
 
         if let Some(c) = c.as_object() {
             // 3. Return ? PromiseResolve(C, x).
-            Self::promise_resolve(c.clone(), x.clone(), context)
+            Self::promise_resolve(c.clone(), x, context)
         } else {
             // 2. If Type(C) is not Object, throw a TypeError exception.
             context.throw_type_error("Promise.resolve() called on a non-object")
@@ -1710,7 +1712,7 @@ impl Promise {
         // 2. Return ? Invoke(promise, "then", « undefined, onRejected »).
         promise.invoke(
             "then",
-            &[JsValue::undefined(), on_rejected.clone()],
+            &[JsValue::undefined(), on_rejected],
             context,
         )
     }
@@ -1777,7 +1779,7 @@ impl Promise {
                             Ok(captures.value.clone())
                         },
                         ReturnValueCaptures {
-                            value: value.clone(),
+                            value,
                         },
                     );
 
@@ -1822,7 +1824,7 @@ impl Promise {
                             Err(captures.reason.clone())
                         },
                         ThrowReasonCaptures {
-                            reason: reason.clone(),
+                            reason,
                         },
                     );
 
@@ -1833,7 +1835,7 @@ impl Promise {
                     promise.invoke("then", &[thrower.into()], context)
                 },
                 FinallyCaptures {
-                    on_finally: on_finally.clone(),
+                    on_finally,
                     c,
                 },
             );
@@ -1846,7 +1848,7 @@ impl Promise {
             // 6. Else,
             //  a. Let thenFinally be onFinally.
             //  b. Let catchFinally be onFinally.
-            (on_finally.clone(), on_finally.clone())
+            (on_finally.clone(), on_finally)
         };
 
         // 7. Return ? Invoke(promise, "then", « thenFinally, catchFinally »).
@@ -1881,11 +1883,11 @@ impl Promise {
         let on_rejected = args.get_or_undefined(1);
 
         // 5. Return PerformPromiseThen(promise, onFulfilled, onRejected, resultCapability).
+        let mut promise_obj = promise_obj.borrow_mut();
         promise_obj
-            .borrow_mut()
             .as_promise_mut()
             .expect("IsPromise(promise) is false")
-            .perform_promise_then(on_fulfilled, on_rejected, Some(result_capability), context)
+            .perform_promise_then(&on_fulfilled, &on_rejected, Some(result_capability), context)
             .pipe(Ok)
     }
 
@@ -1999,7 +2001,7 @@ impl Promise {
         match result_capability {
             // 13. If resultCapability is undefined, then
             //   a. Return undefined.
-            None => JsValue::Undefined,
+            None => JsValue::undefined(),
 
             // 14. Else,
             //   a. Return resultCapability.[[Promise]].
diff --git a/boa_engine/src/builtins/promise/promise_job.rs b/boa_engine/src/builtins/promise/promise_job.rs
index 30b486e93e..f065b0ee95 100644
--- a/boa_engine/src/builtins/promise/promise_job.rs
+++ b/boa_engine/src/builtins/promise/promise_job.rs
@@ -55,7 +55,7 @@ impl PromiseJob {
                     },
                     //   e. Else, let handlerResult be Completion(HostCallJobCallback(handler, undefined, « argument »)).
                     Some(handler) => {
-                        handler.call_job_callback(&JsValue::Undefined, &[argument.clone()], context)
+                        handler.call_job_callback(&JsValue::undefined(), &[argument.clone()], context)
                     }
                 };
 
@@ -69,7 +69,7 @@ impl PromiseJob {
                         );
 
                         // ii. Return empty.
-                        Ok(JsValue::Undefined)
+                        Ok(JsValue::undefined())
                     }
                     Some(promise_capability_record) => {
                         // g. Assert: promiseCapability is a PromiseCapability Record.
@@ -83,13 +83,13 @@ impl PromiseJob {
                             // h. If handlerResult is an abrupt completion, then
                             Err(value) => {
                                 // i. Return ? Call(promiseCapability.[[Reject]], undefined, « handlerResult.[[Value]] »).
-                                context.call(&reject.clone().into(), &JsValue::Undefined, &[value])
+                                context.call(&reject.clone().into(), &JsValue::undefined(), &[value])
                             }
 
                             // i. Else,
                             Ok(value) => {
                                 // i. Return ? Call(promiseCapability.[[Resolve]], undefined, « handlerResult.[[Value]] »).
-                                context.call(&resolve.clone().into(), &JsValue::Undefined, &[value])
+                                context.call(&resolve.clone().into(), &JsValue::undefined(), &[value])
                             }
                         }
                     }
@@ -149,7 +149,7 @@ impl PromiseJob {
                     //    i. Return ? Call(resolvingFunctions.[[Reject]], undefined, « thenCallResult.[[Value]] »).
                     return context.call(
                         &resolving_functions.reject,
-                        &JsValue::Undefined,
+                        &JsValue::undefined(),
                         &[value],
                     );
                 }
diff --git a/boa_engine/src/builtins/proxy/mod.rs b/boa_engine/src/builtins/proxy/mod.rs
index 91f58fa272..31a2bba416 100644
--- a/boa_engine/src/builtins/proxy/mod.rs
+++ b/boa_engine/src/builtins/proxy/mod.rs
@@ -81,7 +81,12 @@ impl Proxy {
         }
 
         // 2. Return ? ProxyCreate(target, handler).
-        Self::create(args.get_or_undefined(0), args.get_or_undefined(1), context).map(JsValue::from)
+        Self::create(
+            &args.get_or_undefined(0),
+            &args.get_or_undefined(1),
+            context,
+        )
+        .map(JsValue::from)
     }
 
     // `10.5.14 ProxyCreate ( target, handler )`
@@ -162,7 +167,11 @@ impl Proxy {
     /// [spec]: https://tc39.es/ecma262/#sec-proxy.revocable
     fn revocable(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let p be ? ProxyCreate(target, handler).
-        let p = Self::create(args.get_or_undefined(0), args.get_or_undefined(1), context)?;
+        let p = Self::create(
+            &args.get_or_undefined(0),
+            &args.get_or_undefined(1),
+            context,
+        )?;
 
         // Revoker creation steps on `Proxy::revoker`
         let revoker = Self::revoker(p.clone(), context);
diff --git a/boa_engine/src/builtins/reflect/mod.rs b/boa_engine/src/builtins/reflect/mod.rs
index 52da25618f..1d7f869199 100644
--- a/boa_engine/src/builtins/reflect/mod.rs
+++ b/boa_engine/src/builtins/reflect/mod.rs
@@ -16,6 +16,7 @@ use crate::{
     object::ObjectInitializer,
     property::Attribute,
     symbol::WellKnownSymbols,
+    value::JsVariant,
     Context, JsResult, JsValue,
 };
 use boa_profiler::Profiler;
@@ -86,7 +87,7 @@ impl Reflect {
             return context.throw_type_error("target must be a function");
         }
         let args = args_list.create_list_from_array_like(&[], context)?;
-        target.call(this_arg, &args, context)
+        target.call(&this_arg, &args, context)
     }
 
     /// Calls a target function as a constructor with arguments.
@@ -104,20 +105,21 @@ impl Reflect {
     ) -> JsResult<JsValue> {
         // 1. If IsConstructor(target) is false, throw a TypeError exception.
         let target = args
-            .get_or_undefined(0)
+            .get_or_undefined(0);
+        let target = target
             .as_constructor()
             .ok_or_else(|| context.construct_type_error("target must be a constructor"))?;
 
         let new_target = if let Some(new_target) = args.get(2) {
             // 3. Else if IsConstructor(newTarget) is false, throw a TypeError exception.
             if let Some(new_target) = new_target.as_constructor() {
-                new_target
+                new_target.clone()
             } else {
                 return context.throw_type_error("newTarget must be a constructor");
             }
         } else {
             // 2. If newTarget is not present, set newTarget to target.
-            target
+            target.clone()
         };
 
         // 4. Let args be ? CreateListFromArrayLike(argumentsList).
@@ -127,7 +129,7 @@ impl Reflect {
 
         // 5. Return ? Construct(target, args, newTarget).
         target
-            .construct(&args, Some(new_target), context)
+            .construct(&args, Some(&new_target), context)
             .map(JsValue::from)
     }
 
@@ -151,7 +153,7 @@ impl Reflect {
         let key = args.get_or_undefined(1).to_property_key(context)?;
         let prop_desc: JsValue = args
             .get(2)
-            .and_then(|v| v.as_object().cloned())
+            .and_then(|v| v.as_object().as_deref().cloned())
             .ok_or_else(|| context.construct_type_error("property descriptor must be an object"))?
             .into();
 
@@ -254,7 +256,7 @@ impl Reflect {
             .ok_or_else(|| context.construct_type_error("target must be an object"))?;
         Ok(target
             .__get_prototype_of__(context)?
-            .map_or(JsValue::Null, JsValue::new))
+            .map_or(JsValue::null(), JsValue::new))
     }
 
     /// Returns `true` if the object has the property, `false` otherwise.
@@ -365,9 +367,7 @@ impl Reflect {
         } else {
             target.clone().into()
         };
-        Ok(target
-            .__set__(key, value.clone(), receiver, context)?
-            .into())
+        Ok(target.__set__(key, value, receiver, context)?.into())
     }
 
     /// Sets the prototype of an object.
@@ -387,9 +387,9 @@ impl Reflect {
             .get(0)
             .and_then(JsValue::as_object)
             .ok_or_else(|| context.construct_type_error("target must be an object"))?;
-        let proto = match args.get_or_undefined(1) {
-            JsValue::Object(obj) => Some(obj.clone()),
-            JsValue::Null => None,
+        let proto = match args.get_or_undefined(1).variant() {
+            JsVariant::Object(obj) => Some(obj.clone()),
+            JsVariant::Null => None,
             _ => return context.throw_type_error("proto must be an object or null"),
         };
         Ok(target.__set_prototype_of__(proto, context)?.into())
diff --git a/boa_engine/src/builtins/regexp/mod.rs b/boa_engine/src/builtins/regexp/mod.rs
index 8ca3f71ea9..367fd1ede7 100644
--- a/boa_engine/src/builtins/regexp/mod.rs
+++ b/boa_engine/src/builtins/regexp/mod.rs
@@ -179,13 +179,13 @@ impl RegExp {
         if new_target.is_undefined() {
             // a. Let newTarget be the active function object.
             // b. If patternIsRegExp is true and flags is undefined, then
-            if let Some(pattern) = pattern_is_regexp {
+            if let Some(ref pattern) = pattern_is_regexp {
                 if flags.is_undefined() {
                     // i. Let patternConstructor be ? Get(pattern, "constructor").
                     let pattern_constructor = pattern.get("constructor", context)?;
                     // ii. If SameValue(newTarget, patternConstructor) is true, return pattern.
                     if JsValue::same_value(new_target, &pattern_constructor) {
-                        return Ok(pattern.clone().into());
+                        return Ok((&**pattern).clone().into());
                     }
                 }
             }
@@ -208,12 +208,12 @@ impl RegExp {
                     JsValue::new(regexp.original_flags.clone()),
                 )
             } else {
-                (JsValue::new(regexp.original_source.clone()), flags.clone())
+                (JsValue::new(regexp.original_source.clone()), flags)
             }
         } else {
             // a. Let P be pattern.
             // b. Let F be flags.
-            (pattern.clone(), flags.clone())
+            (pattern.clone(), flags)
         };
 
         // 7. Let O be ? RegExpAlloc(newTarget).
@@ -352,7 +352,7 @@ impl RegExp {
 
     #[inline]
     fn regexp_has_flag(this: &JsValue, flag: u8, context: &mut Context) -> JsResult<JsValue> {
-        if let Some(object) = this.as_object() {
+        if let Some(ref object) = this.as_object() {
             if let Some(regexp) = object.borrow().as_regexp() {
                 return Ok(JsValue::new(match flag {
                     b'd' => regexp.flags.contains(RegExpFlags::HAS_INDICES),
@@ -695,7 +695,7 @@ impl RegExp {
             .to_string(context)?;
 
         // 4. Let match be ? RegExpExec(R, string).
-        let m = Self::abstract_exec(this, arg_str, context)?;
+        let m = Self::abstract_exec(&this, arg_str, context)?;
 
         // 5. If match is not null, return true; else return false.
         if m.is_some() {
@@ -735,7 +735,7 @@ impl RegExp {
         let arg_str = args.get_or_undefined(0).to_string(context)?;
 
         // 4. Return ? RegExpBuiltinExec(R, S).
-        if let Some(v) = Self::abstract_builtin_exec(obj, &arg_str, context)? {
+        if let Some(v) = Self::abstract_builtin_exec(&obj, &arg_str, context)? {
             Ok(v.into())
         } else {
             Ok(JsValue::null())
@@ -770,7 +770,7 @@ impl RegExp {
             }
 
             // c. Return result.
-            return Ok(result.as_object().cloned());
+            return Ok(result.as_object().as_deref().cloned());
         }
 
         // 5. Perform ? RequireInternalSlot(R, [[RegExpMatcher]]).
@@ -1050,7 +1050,7 @@ impl RegExp {
         #[allow(clippy::if_not_else)]
         if !global {
             // a. Return ? RegExpExec(rx, S).
-            if let Some(v) = Self::abstract_exec(rx, arg_str, context)? {
+            if let Some(v) = Self::abstract_exec(&rx, arg_str, context)? {
                 Ok(v.into())
             } else {
                 Ok(JsValue::null())
@@ -1075,7 +1075,7 @@ impl RegExp {
             // f. Repeat,
             loop {
                 // i. Let result be ? RegExpExec(rx, S).
-                let result = Self::abstract_exec(rx, arg_str.clone(), context)?;
+                let result = Self::abstract_exec(&rx, arg_str.clone(), context)?;
 
                 // ii. If result is null, then
                 // iii. Else,
@@ -1244,9 +1244,10 @@ impl RegExp {
         let length_arg_str = arg_str.encode_utf16().count();
 
         // 5. Let functionalReplace be IsCallable(replaceValue).
-        let mut replace_value = args.get_or_undefined(1).clone();
+        let mut replace_value = args.get_or_undefined(1);
         let functional_replace = replace_value
             .as_object()
+            .as_deref()
             .map(JsObject::is_callable)
             .unwrap_or_default();
 
@@ -1276,7 +1277,7 @@ impl RegExp {
         // 11. Repeat, while done is false,
         loop {
             // a. Let result be ? RegExpExec(rx, S).
-            let result = Self::abstract_exec(rx, arg_str.clone(), context)?;
+            let result = Self::abstract_exec(&rx, arg_str.clone(), context)?;
 
             // b. If result is null, set done to true.
             // c. Else,
@@ -1498,7 +1499,7 @@ impl RegExp {
         }
 
         // 6. Let result be ? RegExpExec(rx, S).
-        let result = Self::abstract_exec(rx, arg_str, context)?;
+        let result = Self::abstract_exec(&rx, arg_str, context)?;
 
         // 7. Let currentLastIndex be ? Get(rx, "lastIndex").
         let current_last_index = rx.get("lastIndex", context)?;
diff --git a/boa_engine/src/builtins/regexp/regexp_string_iterator.rs b/boa_engine/src/builtins/regexp/regexp_string_iterator.rs
index 620d26640b..49c065b8b6 100644
--- a/boa_engine/src/builtins/regexp/regexp_string_iterator.rs
+++ b/boa_engine/src/builtins/regexp/regexp_string_iterator.rs
@@ -81,7 +81,8 @@ impl RegExpStringIterator {
     }
 
     pub fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let mut iterator = this.as_object().map(JsObject::borrow_mut);
+        let iterator = this.as_object();
+        let mut iterator = iterator.as_deref().map(JsObject::borrow_mut);
         let iterator = iterator
             .as_mut()
             .and_then(|obj| obj.as_regexp_string_iterator_mut())
diff --git a/boa_engine/src/builtins/set/mod.rs b/boa_engine/src/builtins/set/mod.rs
index 282f2f7d3d..e827427740 100644
--- a/boa_engine/src/builtins/set/mod.rs
+++ b/boa_engine/src/builtins/set/mod.rs
@@ -142,7 +142,7 @@ impl Set {
         })?;
 
         // 7. Let iteratorRecord be ? GetIterator(iterable).
-        let iterator_record = iterable.clone().get_iterator(context, None, None)?;
+        let iterator_record = iterable.get_iterator(context, None, None)?;
 
         // 8. Repeat,
         //     a. Let next be ? IteratorStep(iteratorRecord).
@@ -224,9 +224,9 @@ impl Set {
         if let Some(object) = this.as_object() {
             if let Some(set) = object.borrow_mut().as_set_mut() {
                 set.add(if value.as_number().map_or(false, |n| n == -0f64) {
-                    JsValue::Integer(0)
+                    JsValue::new(0)
                 } else {
-                    value.clone()
+                    value
                 });
             } else {
                 return context.throw_type_error("'this' is not a Set");
@@ -281,7 +281,7 @@ impl Set {
 
         let res = if let Some(object) = this.as_object() {
             if let Some(set) = object.borrow_mut().as_set_mut() {
-                set.delete(value)
+                set.delete(&value)
             } else {
                 return context.throw_type_error("'this' is not a Set");
             }
@@ -352,7 +352,7 @@ impl Set {
         let this_arg = if this_arg.is_undefined() {
             context.global_object().clone().into()
         } else {
-            this_arg.clone()
+            this_arg
         };
 
         let mut index = 0;
@@ -375,7 +375,7 @@ impl Set {
             index += 1;
         }
 
-        Ok(JsValue::Undefined)
+        Ok(JsValue::undefined())
     }
 
     /// `Map.prototype.has( key )`
@@ -399,7 +399,7 @@ impl Set {
             .and_then(|obj| {
                 obj.borrow()
                     .as_set_ref()
-                    .map(|set| set.contains(value).into())
+                    .map(|set| set.contains(&value).into())
             })
             .ok_or_else(|| context.construct_type_error("'this' is not a Set"))
     }
diff --git a/boa_engine/src/builtins/set/set_iterator.rs b/boa_engine/src/builtins/set/set_iterator.rs
index 4d3e86fc1b..0f2e58cea1 100644
--- a/boa_engine/src/builtins/set/set_iterator.rs
+++ b/boa_engine/src/builtins/set/set_iterator.rs
@@ -67,7 +67,8 @@ impl SetIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%setiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let mut set_iterator = this.as_object().map(JsObject::borrow_mut);
+        let set_iterator = this.as_object();
+        let mut set_iterator = set_iterator.as_deref().map(JsObject::borrow_mut);
 
         let set_iterator = set_iterator
             .as_mut()
@@ -86,7 +87,8 @@ impl SetIterator {
                 ));
             }
 
-            let entries = m.as_object().map(JsObject::borrow);
+            let entries = m.as_object();
+            let entries = entries.as_deref().map(JsObject::borrow);
             let entries = entries
                 .as_ref()
                 .and_then(|obj| obj.as_set_ref())
diff --git a/boa_engine/src/builtins/string/mod.rs b/boa_engine/src/builtins/string/mod.rs
index f77315dd40..075b63b8b5 100644
--- a/boa_engine/src/builtins/string/mod.rs
+++ b/boa_engine/src/builtins/string/mod.rs
@@ -179,8 +179,12 @@ impl String {
         let string = match args.get(0) {
             // 2. Else,
             // a. If NewTarget is undefined and Type(value) is Symbol, return SymbolDescriptiveString(value).
-            Some(JsValue::Symbol(ref sym)) if new_target.is_undefined() => {
-                return Ok(sym.descriptive_string().into())
+            Some(value) if new_target.is_undefined() && value.is_symbol() => {
+                return Ok(value
+                    .as_symbol()
+                    .expect("Already checked for a symbol")
+                    .descriptive_string()
+                    .into())
             }
             // b. Let s be ? ToString(value).
             Some(value) => value.to_string(context)?,
@@ -244,6 +248,7 @@ impl String {
     fn this_string_value(this: &JsValue, context: &mut Context) -> JsResult<JsString> {
         // 1. If Type(value) is String, return value.
         this.as_string()
+            .as_deref()
             .cloned()
             // 2. If Type(value) is Object and value has a [[StringData]] internal slot, then
             //     a. Let s be value.[[StringData]].
@@ -395,7 +400,7 @@ impl String {
         //    If codeUnits is empty, the empty String is returned.
 
         let s = std::string::String::from_utf16_lossy(elements.as_slice());
-        Ok(JsValue::String(JsString::new(s)))
+        Ok(JsValue::new(JsString::new(s)))
     }
 
     /// `String.prototype.toString ( )`
@@ -780,7 +785,7 @@ impl String {
 
         // 3. Let isRegExp be ? IsRegExp(searchString).
         // 4. If isRegExp is true, throw a TypeError exception.
-        if is_reg_exp(search_string, context)? {
+        if is_reg_exp(&search_string, context)? {
             context.throw_type_error(
                 "First argument to String.prototype.startsWith must not be a regular expression",
             )?;
@@ -793,9 +798,11 @@ impl String {
         let len = string.encode_utf16().count() as i64;
 
         // 7. If position is undefined, let pos be 0; else let pos be ? ToIntegerOrInfinity(position).
-        let pos = match args.get_or_undefined(1) {
-            &JsValue::Undefined => IntegerOrInfinity::Integer(0),
-            position => position.to_integer_or_infinity(context)?,
+        let pos = args.get_or_undefined(1);
+        let pos = if pos.is_undefined() {
+            IntegerOrInfinity::Integer(0)
+        } else {
+            pos.to_integer_or_infinity(context)?
         };
 
         // 8. Let start be the result of clamping pos between 0 and len.
@@ -850,7 +857,7 @@ impl String {
         let search_str = match args.get_or_undefined(0) {
             // 3. Let isRegExp be ? IsRegExp(searchString).
             // 4. If isRegExp is true, throw a TypeError exception.
-            search_string if is_reg_exp(search_string, context)? => {
+            search_string if is_reg_exp(&search_string, context)? => {
                 return context.throw_type_error(
                     "First argument to String.prototype.endsWith must not be a regular expression",
                 );
@@ -919,7 +926,7 @@ impl String {
 
         let search_str = match args.get_or_undefined(0) {
             // 3. Let isRegExp be ? IsRegExp(searchString).
-            search_string if is_reg_exp(search_string, context)? => {
+            search_string if is_reg_exp(&search_string, context)? => {
                 return context.throw_type_error(
                     // 4. If isRegExp is true, throw a TypeError exception.
                     "First argument to String.prototype.includes must not be a regular expression",
@@ -979,7 +986,7 @@ impl String {
             if let Some(replacer) = replacer {
                 // i. Return ? Call(replacer, searchValue, « O, replaceValue »).
                 return replacer.call(
-                    search_value,
+                    &search_value,
                     &[this.clone(), replace_value.clone()],
                     context,
                 );
@@ -995,6 +1002,7 @@ impl String {
         // 5. Let functionalReplace be IsCallable(replaceValue).
         let functional_replace = replace_value
             .as_object()
+            .as_deref()
             .map(JsObject::is_callable)
             .unwrap_or_default();
 
@@ -1023,7 +1031,7 @@ impl String {
             // a. Let replacement be ? ToString(? Call(replaceValue, undefined, « searchString, 𝔽(position), string »)).
             context
                 .call(
-                    replace_value,
+                    &replace_value,
                     &JsValue::undefined(),
                     &[search_str.into(), position.into(), this_str.clone().into()],
                 )?
@@ -1088,7 +1096,7 @@ impl String {
         // 2. If searchValue is neither undefined nor null, then
         if !search_value.is_null_or_undefined() {
             // a. Let isRegExp be ? IsRegExp(searchValue).
-            if let Some(obj) = search_value.as_object() {
+            if let Some(ref obj) = search_value.as_object() {
                 // b. If isRegExp is true, then
                 if is_reg_exp_object(obj, context)? {
                     // i. Let flags be ? Get(searchValue, "flags").
@@ -1112,7 +1120,7 @@ impl String {
             // d. If replacer is not undefined, then
             if let Some(replacer) = replacer {
                 // i. Return ? Call(replacer, searchValue, « O, replaceValue »).
-                return replacer.call(search_value, &[o.into(), replace_value.clone()], context);
+                return replacer.call(&search_value, &[o.into(), replace_value.clone()], context);
             }
         }
 
@@ -1125,6 +1133,7 @@ impl String {
         // 5. Let functionalReplace be IsCallable(replaceValue).
         let functional_replace = replace_value
             .as_object()
+            .as_deref()
             .map(JsObject::is_callable)
             .unwrap_or_default();
 
@@ -1196,7 +1205,7 @@ impl String {
                 // i. Let replacement be ? ToString(? Call(replaceValue, undefined, « searchString, 𝔽(p), string »)).
                 context
                     .call(
-                        replace_value,
+                        &replace_value,
                         &JsValue::undefined(),
                         &[
                             search_string.clone().into(),
@@ -1372,7 +1381,7 @@ impl String {
             // b. If matcher is not undefined, then
             if let Some(matcher) = matcher {
                 // i. Return ? Call(matcher, regexp, « O »).
-                return matcher.call(regexp, &[o.clone()], context);
+                return matcher.call(&regexp, &[o.clone()], context);
             }
         }
 
@@ -1380,7 +1389,7 @@ impl String {
         let s = o.to_string(context)?;
 
         // 4. Let rx be ? RegExpCreate(regexp, undefined).
-        let rx = RegExp::create(regexp, &JsValue::Undefined, context)?;
+        let rx = RegExp::create(&regexp, &JsValue::undefined(), context)?;
 
         // 5. Return ? Invoke(rx, @@match, « S »).
         rx.invoke(WellKnownSymbols::r#match(), &[JsValue::new(s)], context)
@@ -1485,7 +1494,7 @@ impl String {
         let fill_string = args.get_or_undefined(1);
 
         // 2. Return ? StringPad(O, maxLength, fillString, end).
-        Self::string_pad(this, max_length, fill_string, Placement::End, context)
+        Self::string_pad(this, &max_length, &fill_string, Placement::End, context)
     }
 
     /// `String.prototype.padStart( targetLength [, padString] )`
@@ -1512,7 +1521,7 @@ impl String {
         let fill_string = args.get_or_undefined(1);
 
         // 2. Return ? StringPad(O, maxLength, fillString, start).
-        Self::string_pad(this, max_length, fill_string, Placement::Start, context)
+        Self::string_pad(this, &max_length, &fill_string, Placement::Start, context)
     }
 
     /// String.prototype.trim()
@@ -1676,9 +1685,11 @@ impl String {
         let int_start = args.get_or_undefined(0).to_integer_or_infinity(context)?;
 
         // 5. If end is undefined, let intEnd be len; else let intEnd be ? ToIntegerOrInfinity(end).
-        let int_end = match args.get_or_undefined(1) {
-            &JsValue::Undefined => IntegerOrInfinity::Integer(len),
-            end => end.to_integer_or_infinity(context)?,
+        let end = args.get_or_undefined(1);
+        let int_end = if end.is_undefined() {
+            IntegerOrInfinity::Integer(len)
+        } else {
+            end.to_integer_or_infinity(context)?
         };
 
         // 6. Let finalStart be the result of clamping intStart between 0 and len.
@@ -1733,9 +1744,11 @@ impl String {
 
         // 7. If length is undefined, let intLength be size; otherwise let intLength be ? ToIntegerOrInfinity(length).
         // Moved it before to ensure an error throws before returning the empty string on `match int_start`
-        let int_length = match args.get_or_undefined(1) {
-            &JsValue::Undefined => IntegerOrInfinity::Integer(size),
-            val => val.to_integer_or_infinity(context)?,
+        let length = args.get_or_undefined(1);
+        let int_length = if length.is_undefined() {
+            IntegerOrInfinity::Integer(size)
+        } else {
+            length.to_integer_or_infinity(context)?
         };
 
         let int_start = match int_start {
@@ -1798,7 +1811,7 @@ impl String {
             // b. If splitter is not undefined, then
             if let Some(splitter) = splitter {
                 // i. Return ? Call(splitter, separator, « O, limit »).
-                return splitter.call(separator, &[this.clone(), limit.clone()], context);
+                return splitter.call(&separator, &[this.clone(), limit.clone()], context);
             }
         }
 
@@ -1983,7 +1996,7 @@ impl String {
             let matcher = regexp.get_method(WellKnownSymbols::match_all(), context)?;
             // d. If matcher is not undefined, then
             if let Some(matcher) = matcher {
-                return matcher.call(regexp, &[o.clone()], context);
+                return matcher.call(&regexp, &[o.clone()], context);
             }
         }
 
@@ -1991,7 +2004,7 @@ impl String {
         let s = o.to_string(context)?;
 
         // 4. Let rx be ? RegExpCreate(regexp, "g").
-        let rx = RegExp::create(regexp, &JsValue::new("g"), context)?;
+        let rx = RegExp::create(&regexp, &JsValue::new("g"), context)?;
 
         // 5. Return ? Invoke(rx, @@matchAll, « S »).
         rx.invoke(WellKnownSymbols::match_all(), &[JsValue::new(s)], context)
@@ -2072,7 +2085,7 @@ impl String {
             // b. If searcher is not undefined, then
             if let Some(searcher) = searcher {
                 // i. Return ? Call(searcher, regexp, « O »).
-                return searcher.call(regexp, &[o.clone()], context);
+                return searcher.call(&regexp, &[o.clone()], context);
             }
         }
 
@@ -2080,7 +2093,7 @@ impl String {
         let string = o.to_string(context)?;
 
         // 4. Let rx be ? RegExpCreate(regexp, undefined).
-        let rx = RegExp::create(regexp, &JsValue::Undefined, context)?;
+        let rx = RegExp::create(&regexp, &JsValue::undefined(), context)?;
 
         // 5. Return ? Invoke(rx, @@search, « string »).
         rx.invoke(WellKnownSymbols::search(), &[JsValue::new(string)], context)
@@ -2193,7 +2206,7 @@ pub(crate) fn get_substitution(
                         result.push(second);
                         result.push(*third);
                     } else if let Some(capture) = captures.get(nn - 1) {
-                        if let Some(s) = capture.as_string() {
+                        if let Some(ref s) = capture.as_string() {
                             result.push_str(s);
                         }
                     }
@@ -2214,7 +2227,7 @@ pub(crate) fn get_substitution(
                         result.push('$');
                         result.push(second);
                     } else if let Some(capture) = captures.get(n - 1) {
-                        if let Some(s) = capture.as_string() {
+                        if let Some(ref s) = capture.as_string() {
                             result.push_str(s);
                         }
                     }
@@ -2324,12 +2337,13 @@ fn split_match(s_str: &str, q: usize, r_str: &str) -> Option<usize> {
 /// [spec]: https://tc39.es/ecma262/#sec-isregexp
 fn is_reg_exp(argument: &JsValue, context: &mut Context) -> JsResult<bool> {
     // 1. If Type(argument) is not Object, return false.
-    let argument = match argument {
-        JsValue::Object(o) => o,
-        _ => return Ok(false),
+    let argument = if let Some(o) = argument.as_object() {
+        o
+    } else {
+        return Ok(false);
     };
 
-    is_reg_exp_object(argument, context)
+    is_reg_exp_object(&argument, context)
 }
 fn is_reg_exp_object(argument: &JsObject, context: &mut Context) -> JsResult<bool> {
     // 2. Let matcher be ? Get(argument, @@match).
diff --git a/boa_engine/src/builtins/string/string_iterator.rs b/boa_engine/src/builtins/string/string_iterator.rs
index 09983f532a..1530decb8e 100644
--- a/boa_engine/src/builtins/string/string_iterator.rs
+++ b/boa_engine/src/builtins/string/string_iterator.rs
@@ -37,7 +37,8 @@ impl StringIterator {
     }
 
     pub fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let mut string_iterator = this.as_object().map(JsObject::borrow_mut);
+        let string_iterator = this.as_object();
+        let mut string_iterator = string_iterator.as_deref().map(JsObject::borrow_mut);
         let string_iterator = string_iterator
             .as_mut()
             .and_then(|obj| obj.as_string_iterator_mut())
diff --git a/boa_engine/src/builtins/symbol/mod.rs b/boa_engine/src/builtins/symbol/mod.rs
index 3dd58078e4..f1a85f4760 100644
--- a/boa_engine/src/builtins/symbol/mod.rs
+++ b/boa_engine/src/builtins/symbol/mod.rs
@@ -192,6 +192,8 @@ impl Symbol {
     fn this_symbol_value(value: &JsValue, context: &mut Context) -> JsResult<JsSymbol> {
         value
             .as_symbol()
+            .as_deref()
+            .cloned()
             .or_else(|| value.as_object().and_then(|obj| obj.borrow().as_symbol()))
             .ok_or_else(|| context.construct_type_error("'this' is not a Symbol"))
     }
@@ -236,7 +238,7 @@ impl Symbol {
     ) -> JsResult<JsValue> {
         // 1. Return ? thisSymbolValue(this value).
         let symbol = Self::this_symbol_value(this, context)?;
-        Ok(JsValue::Symbol(symbol))
+        Ok(JsValue::new(symbol))
     }
 
     /// `get Symbol.prototype.description`
@@ -307,14 +309,14 @@ impl Symbol {
     ) -> JsResult<JsValue> {
         let sym = args.get_or_undefined(0);
         // 1. If Type(sym) is not Symbol, throw a TypeError exception.
-        if let Some(sym) = sym.as_symbol() {
+        if let Some(ref sym) = sym.as_symbol() {
             // 2. For each element e of the GlobalSymbolRegistry List (see 20.4.2.2), do
             //     a. If SameValue(e.[[Symbol]], sym) is true, return e.[[Key]].
             // 3. Assert: GlobalSymbolRegistry does not currently contain an entry for sym.
             // 4. Return undefined.
             let symbol = GLOBAL_SYMBOL_REGISTRY.with(move |registry| {
                 let registry = registry.borrow();
-                registry.get_symbol(&sym)
+                registry.get_symbol(sym)
             });
 
             Ok(symbol.map(JsValue::from).unwrap_or_default())
diff --git a/boa_engine/src/builtins/typed_array/mod.rs b/boa_engine/src/builtins/typed_array/mod.rs
index 0315cf0693..5233ca7ac0 100644
--- a/boa_engine/src/builtins/typed_array/mod.rs
+++ b/boa_engine/src/builtins/typed_array/mod.rs
@@ -26,7 +26,7 @@ use crate::{
     },
     property::{Attribute, PropertyNameKind},
     symbol::WellKnownSymbols,
-    value::{IntegerOrInfinity, JsValue},
+    value::{IntegerOrInfinity, JsValue, JsVariant},
     Context, JsResult, JsString,
 };
 use boa_profiler::Profiler;
@@ -161,7 +161,7 @@ macro_rules! typed_array {
                     // ii. If firstArgument has a [[TypedArrayName]] internal slot, then
                     if first_argument.is_typed_array() {
                         // 1. Perform ? InitializeTypedArrayFromTypedArray(O, firstArgument).
-                        TypedArray::initialize_from_typed_array(&o, first_argument, context)?;
+                        TypedArray::initialize_from_typed_array(&o, &first_argument, context)?;
                     } else if first_argument.is_array_buffer() {
                         // iii. Else if firstArgument has an [[ArrayBufferData]] internal slot, then
 
@@ -175,8 +175,8 @@ macro_rules! typed_array {
                         TypedArray::initialize_from_array_buffer(
                             &o,
                             first_argument.clone(),
-                            byte_offset,
-                            length,
+                            &byte_offset,
+                            &length,
                             context,
                         )?;
                     } else {
@@ -407,7 +407,9 @@ impl TypedArray {
 
         let mapping = match args.get(1) {
             // 3. If mapfn is undefined, let mapping be false.
-            None | Some(JsValue::Undefined) => None,
+            None => None,
+            Some(v) if v.is_undefined() => None,
+
             // 4. Else,
             Some(v) => match v.as_object() {
                 // b. Let mapping be true.
@@ -429,11 +431,11 @@ impl TypedArray {
         // 6. If usingIterator is not undefined, then
         if let Some(using_iterator) = using_iterator {
             // a. Let values be ? IterableToList(source, usingIterator).
-            let values = iterable_to_list(context, source, Some(using_iterator.into()))?;
+            let values = iterable_to_list(context, &source, Some(using_iterator.into()))?;
 
             // b. Let len be the number of elements in values.
             // c. Let targetObj be ? TypedArrayCreate(C, « 𝔽(len) »).
-            let target_obj = Self::create(constructor, &[values.len().into()], context)?;
+            let target_obj = Self::create(&constructor, &[values.len().into()], context)?;
 
             // d. Let k be 0.
             // e. Repeat, while k < len,
@@ -443,7 +445,7 @@ impl TypedArray {
                 // iii. If mapping is true, then
                 let mapped_value = if let Some(map_fn) = &mapping {
                     // 1. Let mappedValue be ? Call(mapfn, thisArg, « kValue, 𝔽(k) »).
-                    map_fn.call(this_arg, &[k_value.clone(), k.into()], context)?
+                    map_fn.call(&this_arg, &[k_value.clone(), k.into()], context)?
                 }
                 // iv. Else, let mappedValue be kValue.
                 else {
@@ -469,7 +471,7 @@ impl TypedArray {
         let len = array_like.length_of_array_like(context)?;
 
         // 10. Let targetObj be ? TypedArrayCreate(C, « 𝔽(len) »).
-        let target_obj = Self::create(constructor, &[len.into()], context)?;
+        let target_obj = Self::create(&constructor, &[len.into()], context)?;
 
         // 11. Let k be 0.
         // 12. Repeat, while k < len,
@@ -481,7 +483,7 @@ impl TypedArray {
             // c. If mapping is true, then
             let mapped_value = if let Some(map_fn) = &mapping {
                 // i. Let mappedValue be ? Call(mapfn, thisArg, « kValue, 𝔽(k) »).
-                map_fn.call(this_arg, &[k_value, k.into()], context)?
+                map_fn.call(&this_arg, &[k_value, k.into()], context)?
             }
             // d. Else, let mappedValue be kValue.
             else {
@@ -515,7 +517,7 @@ impl TypedArray {
         };
 
         // 4. Let newObj be ? TypedArrayCreate(C, « 𝔽(len) »).
-        let new_obj = Self::create(constructor, &[args.len().into()], context)?;
+        let new_obj = Self::create(&constructor, &[args.len().into()], context)?;
 
         // 5. Let k be 0.
         // 6. Repeat, while k < len,
@@ -612,7 +614,7 @@ impl TypedArray {
         // 5. Return buffer.
         Ok(typed_array
             .viewed_array_buffer()
-            .map_or_else(JsValue::undefined, |buffer| buffer.clone().into()))
+            .map_or(JsValue::undefined(), |buffer| buffer.clone().into()))
     }
 
     /// `23.2.3.3 get %TypedArray%.prototype.byteLength`
@@ -906,7 +908,8 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback_fn = match args.get_or_undefined(0).as_object() {
+        let callback_fn = args.get_or_undefined(0);
+        let callback_fn = match callback_fn.as_object() {
             Some(obj) if obj.is_callable() => obj,
             _ => {
                 return context.throw_type_error(
@@ -925,7 +928,7 @@ impl TypedArray {
             // c. Let testResult be ! ToBoolean(? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »)).
             let test_result = callback_fn
                 .call(
-                    args.get_or_undefined(1),
+                    &args.get_or_undefined(1),
                     &[k_value, k.into(), this.clone()],
                     context,
                 )?
@@ -1053,7 +1056,8 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback_fn = match args.get_or_undefined(0).as_object() {
+        let callback_fn = args.get_or_undefined(0);
+        let callback_fn = match callback_fn.as_object() {
             Some(obj) if obj.is_callable() => obj,
             _ => {
                 return context.throw_type_error(
@@ -1078,7 +1082,7 @@ impl TypedArray {
             // c. Let selected be ! ToBoolean(? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »)).#
             let selected = callback_fn
                 .call(
-                    args.get_or_undefined(1),
+                    &args.get_or_undefined(1),
                     &[k_value.clone(), k.into(), this.clone()],
                     context,
                 )?
@@ -1095,7 +1099,7 @@ impl TypedArray {
         }
 
         // 9. Let A be ? TypedArraySpeciesCreate(O, « 𝔽(captured) »).
-        let a = Self::species_create(obj, o.typed_array_name(), &[captured.into()], context)?;
+        let a = Self::species_create(&obj, o.typed_array_name(), &[captured.into()], context)?;
 
         // 10. Let n be 0.
         // 11. For each element e of kept, do
@@ -1138,7 +1142,8 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(predicate) is false, throw a TypeError exception.
-        let predicate = match args.get_or_undefined(0).as_object() {
+        let predicate = args.get_or_undefined(0);
+        let predicate = match predicate.as_object() {
             Some(obj) if obj.is_callable() => obj,
             _ => {
                 return context.throw_type_error(
@@ -1158,7 +1163,7 @@ impl TypedArray {
             // d. If testResult is true, return kValue.
             if predicate
                 .call(
-                    args.get_or_undefined(1),
+                    &args.get_or_undefined(1),
                     &[k_value.clone(), k.into(), this.clone()],
                     context,
                 )?
@@ -1200,8 +1205,9 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(predicate) is false, throw a TypeError exception.
+        let predicate = args.get_or_undefined(0);
         let predicate =
-            match args.get_or_undefined(0).as_object() {
+            match predicate.as_object() {
                 Some(obj) if obj.is_callable() => obj,
                 _ => return context.throw_type_error(
                     "TypedArray.prototype.findindex called with non-callable predicate function",
@@ -1219,7 +1225,7 @@ impl TypedArray {
             // d. If testResult is true, return 𝔽(k).
             if predicate
                 .call(
-                    args.get_or_undefined(1),
+                    &args.get_or_undefined(1),
                     &[k_value.clone(), k.into(), this.clone()],
                     context,
                 )?
@@ -1261,7 +1267,8 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback_fn = match args.get_or_undefined(0).as_object() {
+        let callback_fn = args.get_or_undefined(0);
+        let callback_fn = match callback_fn.as_object() {
             Some(obj) if obj.is_callable() => obj,
             _ => {
                 return context.throw_type_error(
@@ -1279,7 +1286,7 @@ impl TypedArray {
 
             // c. Perform ? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »).
             callback_fn.call(
-                args.get_or_undefined(1),
+                &args.get_or_undefined(1),
                 &[k_value, k.into(), this.clone()],
                 context,
             )?;
@@ -1354,7 +1361,7 @@ impl TypedArray {
             let element_k = obj.get(k, context).expect("Get cannot fail here");
 
             // b. If SameValueZero(searchElement, elementK) is true, return true.
-            if JsValue::same_value_zero(args.get_or_undefined(0), &element_k) {
+            if JsValue::same_value_zero(&args.get_or_undefined(0), &element_k) {
                 return Ok(true.into());
             }
 
@@ -1680,7 +1687,8 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback_fn = match args.get_or_undefined(0).as_object() {
+        let callback_fn = args.get_or_undefined(0);
+        let callback_fn = match callback_fn.as_object() {
             Some(obj) if obj.is_callable() => obj,
             _ => {
                 return context.throw_type_error(
@@ -1690,7 +1698,7 @@ impl TypedArray {
         };
 
         // 5. Let A be ? TypedArraySpeciesCreate(O, « 𝔽(len) »).
-        let a = Self::species_create(obj, o.typed_array_name(), &[len.into()], context)?;
+        let a = Self::species_create(&obj, o.typed_array_name(), &[len.into()], context)?;
 
         // 6. Let k be 0.
         // 7. Repeat, while k < len,
@@ -1701,7 +1709,7 @@ impl TypedArray {
 
             // c. Let mappedValue be ? Call(callbackfn, thisArg, « kValue, 𝔽(k), O »).
             let mapped_value = callback_fn.call(
-                args.get_or_undefined(1),
+                &args.get_or_undefined(1),
                 &[k_value, k.into(), this.clone()],
                 context,
             )?;
@@ -1742,7 +1750,8 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback_fn = match args.get_or_undefined(0).as_object() {
+        let callback_fn = args.get_or_undefined(0);
+        let callback_fn = match callback_fn.as_object() {
             Some(obj) if obj.is_callable() => obj,
             _ => {
                 return context.throw_type_error(
@@ -1823,8 +1832,9 @@ impl TypedArray {
         let len = o.array_length() as i64;
 
         // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
+        let callback_fn = args.get_or_undefined(0);
         let callback_fn =
-            match args.get_or_undefined(0).as_object() {
+            match callback_fn.as_object() {
                 Some(obj) if obj.is_callable() => obj,
                 _ => return context.throw_type_error(
                     "TypedArray.prototype.reduceright called with non-callable callback function",
@@ -1974,16 +1984,16 @@ impl TypedArray {
         }
 
         let source = args.get_or_undefined(0);
-        match source {
+        match source.variant() {
             // 6. If source is an Object that has a [[TypedArrayName]] internal slot, then
-            JsValue::Object(source) if source.is_typed_array() => {
+            JsVariant::Object(source) if source.is_typed_array() => {
                 // a. Perform ? SetTypedArrayFromTypedArray(target, targetOffset, source).
-                Self::set_typed_array_from_typed_array(target, target_offset, source, context)?;
+                Self::set_typed_array_from_typed_array(&target, target_offset, &source, context)?;
             }
             // 7. Else,
             _ => {
                 // a. Perform ? SetTypedArrayFromArrayLike(target, targetOffset, source).
-                Self::set_typed_array_from_array_like(target, target_offset, source, context)?;
+                Self::set_typed_array_from_array_like(&target, target_offset, &source, context)?;
             }
         }
 
@@ -2380,7 +2390,7 @@ impl TypedArray {
         let count = std::cmp::max(r#final - k, 0) as u64;
 
         // 13. Let A be ? TypedArraySpeciesCreate(O, « 𝔽(count) »).
-        let a = Self::species_create(obj, o.typed_array_name(), &[count.into()], context)?;
+        let a = Self::species_create(&obj, o.typed_array_name(), &[count.into()], context)?;
         let a_borrow = a.borrow();
         let a_array = a_borrow
             .as_typed_array()
@@ -2517,7 +2527,8 @@ impl TypedArray {
         let len = o.array_length();
 
         // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
-        let callback_fn = match args.get_or_undefined(0).as_object() {
+        let callback_fn = args.get_or_undefined(0);
+        let callback_fn = match callback_fn.as_object() {
             Some(obj) if obj.is_callable() => obj,
             _ => {
                 return context.throw_type_error(
@@ -2537,7 +2548,7 @@ impl TypedArray {
             // d. If testResult is true, return true.
             if callback_fn
                 .call(
-                    args.get_or_undefined(1),
+                    &args.get_or_undefined(1),
                     &[k_value, k.into(), this.clone()],
                     context,
                 )?
@@ -2563,9 +2574,9 @@ impl TypedArray {
         context: &mut Context,
     ) -> JsResult<JsValue> {
         // 1. If comparefn is not undefined and IsCallable(comparefn) is false, throw a TypeError exception.
-        let compare_fn = match args.get(0) {
-            None | Some(JsValue::Undefined) => None,
-            Some(JsValue::Object(obj)) if obj.is_callable() => Some(obj),
+        let compare_fn = match args.get(0).map(JsValue::variant) {
+            None | Some(JsVariant::Undefined) => None,
+            Some(JsVariant::Object(obj)) if obj.is_callable() => Some(obj),
             _ => {
                 return context
                     .throw_type_error("TypedArray.sort called with non-callable comparefn")
@@ -2649,7 +2660,7 @@ impl TypedArray {
                 return Ok(v.partial_cmp(&0.0).unwrap_or(Ordering::Equal));
             }
 
-            if let (JsValue::BigInt(x), JsValue::BigInt(y)) = (x, y) {
+            if let (Some(x), Some(y)) = (x.as_bigint(), y.as_bigint()) {
                 // 6. If x < y, return -1𝔽.
                 if x < y {
                     return Ok(Ordering::Less);
@@ -2734,7 +2745,7 @@ impl TypedArray {
         let mut sort_err = Ok(());
         items.sort_by(|x, y| {
             if sort_err.is_ok() {
-                sort_compare(x, y, compare_fn, context).unwrap_or_else(|err| {
+                sort_compare(x, y, compare_fn.as_deref(), context).unwrap_or_else(|err| {
                     sort_err = Err(err);
                     Ordering::Equal
                 })
@@ -2838,7 +2849,7 @@ impl TypedArray {
         // 19. Let argumentsList be « buffer, 𝔽(beginByteOffset), 𝔽(newLength) ».
         // 20. Return ? TypedArraySpeciesCreate(O, argumentsList).
         Ok(Self::species_create(
-            obj,
+            &obj,
             o.typed_array_name(),
             &[
                 buffer.clone().into(),
@@ -2901,7 +2912,7 @@ impl TypedArray {
                     .as_typed_array()
                     .map(|o| o.typed_array_name().name().into())
             })
-            .unwrap_or(JsValue::Undefined))
+            .unwrap_or(JsValue::undefined()))
     }
 
     /// `23.2.4.1 TypedArraySpeciesCreate ( exemplar, argumentList )`
diff --git a/boa_engine/src/class.rs b/boa_engine/src/class.rs
index cbbb8a2eda..750b3c180f 100644
--- a/boa_engine/src/class.rs
+++ b/boa_engine/src/class.rs
@@ -111,7 +111,7 @@ impl<T: Class> ClassConstructor for T {
         }
 
         let class_constructor = context.global_object().clone().get(T::NAME, context)?;
-        let class_constructor = if let JsValue::Object(ref obj) = class_constructor {
+        let class_constructor = if let Some(obj) = class_constructor.as_object() {
             obj
         } else {
             return context.throw_type_error(format!(
@@ -120,8 +120,8 @@ impl<T: Class> ClassConstructor for T {
             ));
         };
         let class_prototype =
-            if let JsValue::Object(ref obj) = class_constructor.get(PROTOTYPE, context)? {
-                obj.clone()
+            if let Some(object) = class_constructor.get(PROTOTYPE, context)?.as_object() {
+                object.clone()
             } else {
                 return context.throw_type_error(format!(
                     "invalid default prototype for native class `{}`",
@@ -131,10 +131,10 @@ impl<T: Class> ClassConstructor for T {
 
         let prototype = this
             .as_object()
-            .cloned()
+            .as_deref()
             .map(|obj| {
                 obj.get(PROTOTYPE, context)
-                    .map(|val| val.as_object().cloned())
+                    .map(|val| val.as_object().as_deref().cloned())
             })
             .transpose()?
             .flatten()
diff --git a/boa_engine/src/context/mod.rs b/boa_engine/src/context/mod.rs
index d2d35e873a..09626cb060 100644
--- a/boa_engine/src/context/mod.rs
+++ b/boa_engine/src/context/mod.rs
@@ -743,7 +743,7 @@ impl Context {
     /// Runs all the jobs in the job queue.
     fn run_queued_jobs(&mut self) -> JsResult<()> {
         while let Some(job) = self.promise_job_queue.pop_front() {
-            job.call_job_callback(&JsValue::Undefined, &[], self)?;
+            job.call_job_callback(&JsValue::undefined(), &[], self)?;
         }
         Ok(())
     }
diff --git a/boa_engine/src/environments/compile.rs b/boa_engine/src/environments/compile.rs
index 9bea4ba6f2..2aff17505a 100644
--- a/boa_engine/src/environments/compile.rs
+++ b/boa_engine/src/environments/compile.rs
@@ -300,7 +300,7 @@ impl Context {
                 self.global_bindings_mut().insert(
                     name_str,
                     PropertyDescriptor::builder()
-                        .value(JsValue::Undefined)
+                        .value(JsValue::undefined())
                         .writable(true)
                         .enumerable(true)
                         .configurable(true)
diff --git a/boa_engine/src/environments/runtime.rs b/boa_engine/src/environments/runtime.rs
index 21ecf3aed0..56469c3e7f 100644
--- a/boa_engine/src/environments/runtime.rs
+++ b/boa_engine/src/environments/runtime.rs
@@ -402,7 +402,7 @@ impl DeclarativeEnvironmentStack {
         let this = if let Some(this) = this {
             this
         } else {
-            JsValue::Null
+            JsValue::null()
         };
 
         self.stack.push(Gc::new(DeclarativeEnvironment {
diff --git a/boa_engine/src/lib.rs b/boa_engine/src/lib.rs
index 9e6e3ea26c..676d1fcc7f 100644
--- a/boa_engine/src/lib.rs
+++ b/boa_engine/src/lib.rs
@@ -5,6 +5,8 @@
 //!  - **serde** - Enables serialization and deserialization of the AST (Abstract Syntax Tree).
 //!  - **console** - Enables `boa`'s [WHATWG `console`][whatwg] object implementation.
 //!  - **profiler** - Enables profiling with measureme (this is mostly internal).
+//!  - **nan_boxing** - Enables `boa`'s nan-boxed [`JsValue`] implementation
+//! (Only available on x86_64 platforms, does nothing on incompatible platforms).
 //!  - **intl** - Enables `boa`'s [ECMA-402 Internationalization API][ecma-402] (`Intl` object)
 //!
 //! [whatwg]: https://console.spec.whatwg.org
@@ -70,11 +72,11 @@
     // Ignore because `write!(string, ...)` instead of `string.push_str(&format!(...))` can fail.
     // We only use it in `ToInternedString` where performance is not an issue.
     clippy::format_push_string,
-    // TODO deny once false positive are fixed (https://github.com/rust-lang/rust-clippy/issues/9076).
-    clippy::trait_duplication_in_bounds,
     rustdoc::missing_doc_code_examples
 )]
 
+pub mod value; // In the top to give priority to `JsValue` docs
+
 pub mod bigint;
 pub mod builtins;
 pub mod bytecompiler;
@@ -88,7 +90,6 @@ pub mod realm;
 pub mod string;
 pub mod symbol;
 pub mod syntax;
-pub mod value;
 pub mod vm;
 
 #[cfg(test)]
diff --git a/boa_engine/src/object/internal_methods/proxy.rs b/boa_engine/src/object/internal_methods/proxy.rs
index c70175923d..7f8a1465e9 100644
--- a/boa_engine/src/object/internal_methods/proxy.rs
+++ b/boa_engine/src/object/internal_methods/proxy.rs
@@ -2,7 +2,7 @@ use crate::{
     builtins::{array, object::Object},
     object::{InternalObjectMethods, JsObject, JsPrototype},
     property::{PropertyDescriptor, PropertyKey},
-    value::Type,
+    value::{JsVariant, Type},
     Context, JsResult, JsValue,
 };
 use rustc_hash::FxHashSet;
@@ -76,9 +76,9 @@ pub(crate) fn proxy_exotic_get_prototype_of(
     let handler_proto = trap.call(&handler.into(), &[target.clone().into()], context)?;
 
     // 8. If Type(handlerProto) is neither Object nor Null, throw a TypeError exception.
-    let handler_proto = match &handler_proto {
-        JsValue::Object(obj) => Some(obj.clone()),
-        JsValue::Null => None,
+    let handler_proto = match handler_proto.variant() {
+        JsVariant::Object(obj) => Some(obj.clone()),
+        JsVariant::Null => None,
         _ => return context.throw_type_error("Proxy trap result is neither object nor null"),
     };
 
@@ -138,7 +138,7 @@ pub(crate) fn proxy_exotic_set_prototype_of(
             &handler.into(),
             &[
                 target.clone().into(),
-                val.clone().map_or(JsValue::Null, Into::into),
+                val.clone().map_or(JsValue::null(), Into::into),
             ],
             context,
         )?
@@ -679,7 +679,11 @@ pub(crate) fn proxy_exotic_set(
             if target_desc.is_accessor_descriptor() {
                 // i. If targetDesc.[[Set]] is undefined, throw a TypeError exception.
                 match target_desc.set() {
-                    None | Some(&JsValue::Undefined) => {
+                    None => {
+                        return context
+                            .throw_type_error("Proxy trap set unexpected accessor descriptor");
+                    }
+                    Some(v) if v.is_undefined() => {
                         return context
                             .throw_type_error("Proxy trap set unexpected accessor descriptor");
                     }
@@ -800,8 +804,8 @@ pub(crate) fn proxy_exotic_own_property_keys(
     let mut unchecked_result_keys: FxHashSet<PropertyKey> = FxHashSet::default();
     let mut trap_result = Vec::new();
     for value in &trap_result_raw {
-        match value {
-            JsValue::String(s) => {
+        match value.variant() {
+            JsVariant::String(s) => {
                 if !unchecked_result_keys.insert(s.clone().into()) {
                     return context.throw_type_error(
                         "Proxy trap result contains duplicate string property keys",
@@ -809,7 +813,7 @@ pub(crate) fn proxy_exotic_own_property_keys(
                 }
                 trap_result.push(s.clone().into());
             }
-            JsValue::Symbol(s) => {
+            JsVariant::Symbol(s) => {
                 if !unchecked_result_keys.insert(s.clone().into()) {
                     return context.throw_type_error(
                         "Proxy trap result contains duplicate symbol property keys",
@@ -984,10 +988,10 @@ fn proxy_exotic_construct(
     )?;
 
     // 10. If Type(newObj) is not Object, throw a TypeError exception.
-    let new_obj = new_obj.as_object().cloned().ok_or_else(|| {
+    let new_obj = new_obj.as_object().ok_or_else(|| {
         context.construct_type_error("Proxy trap constructor returned non-object value")
     })?;
 
     // 11. Return newObj.
-    Ok(new_obj)
+    Ok(new_obj.clone())
 }
diff --git a/boa_engine/src/object/jsarray.rs b/boa_engine/src/object/jsarray.rs
index ddb7fcedd5..66652afa18 100644
--- a/boa_engine/src/object/jsarray.rs
+++ b/boa_engine/src/object/jsarray.rs
@@ -109,6 +109,7 @@ impl JsArray {
     pub fn concat(&self, items: &[JsValue], context: &mut Context) -> JsResult<Self> {
         let object = Array::concat(&self.inner.clone().into(), items, context)?
             .as_object()
+            .as_deref()
             .cloned()
             .expect("Array.prototype.filter should always return object");
 
@@ -124,6 +125,7 @@ impl JsArray {
         )
         .map(|x| {
             x.as_string()
+                .as_deref()
                 .cloned()
                 .expect("Array.prototype.join always returns string")
         })
@@ -231,6 +233,7 @@ impl JsArray {
             context,
         )?
         .as_object()
+        .as_deref()
         .cloned()
         .expect("Array.prototype.filter should always return object");
 
@@ -250,6 +253,7 @@ impl JsArray {
             context,
         )?
         .as_object()
+        .as_deref()
         .cloned()
         .expect("Array.prototype.map should always return object");
 
@@ -316,6 +320,7 @@ impl JsArray {
             context,
         )?
         .as_object()
+        .as_deref()
         .cloned()
         .expect("Array.prototype.slice should always return object");
 
diff --git a/boa_engine/src/object/jsarraybuffer.rs b/boa_engine/src/object/jsarraybuffer.rs
index 95d6514af0..002e459d8c 100644
--- a/boa_engine/src/object/jsarraybuffer.rs
+++ b/boa_engine/src/object/jsarraybuffer.rs
@@ -69,7 +69,7 @@ impl JsArrayBuffer {
         obj.borrow_mut().data = ObjectData::array_buffer(ArrayBuffer {
             array_buffer_data: Some(block),
             array_buffer_byte_length: byte_length as u64,
-            array_buffer_detach_key: JsValue::Undefined,
+            array_buffer_detach_key: JsValue::undefined(),
         });
 
         Ok(Self { inner: obj })
diff --git a/boa_engine/src/object/jsobject.rs b/boa_engine/src/object/jsobject.rs
index 4f1b2f4809..171d07ee9b 100644
--- a/boa_engine/src/object/jsobject.rs
+++ b/boa_engine/src/object/jsobject.rs
@@ -6,7 +6,7 @@ use super::{JsPrototype, NativeObject, Object, PropertyMap};
 use crate::{
     object::{ObjectData, ObjectKind},
     property::{PropertyDescriptor, PropertyKey},
-    value::PreferredType,
+    value::{PointerType, PreferredType},
     Context, JsResult, JsValue,
 };
 use boa_gc::{self, Finalize, Gc, Trace};
@@ -16,6 +16,7 @@ use std::{
     collections::HashMap,
     error::Error,
     fmt::{self, Debug, Display},
+    mem::{self, ManuallyDrop},
     result::Result as StdResult,
 };
 
@@ -31,6 +32,16 @@ pub struct JsObject {
     inner: Gc<boa_gc::Cell<Object>>,
 }
 
+unsafe impl PointerType for JsObject {
+    unsafe fn from_void_ptr(ptr: *mut ()) -> ManuallyDrop<Self> {
+        ManuallyDrop::new(mem::transmute(ptr))
+    }
+
+    unsafe fn into_void_ptr(object: ManuallyDrop<Self>) -> *mut () {
+        mem::transmute(object)
+    }
+}
+
 impl JsObject {
     /// Create a new `JsObject` from an internal `Object`.
     #[inline]
diff --git a/boa_engine/src/object/jsset.rs b/boa_engine/src/object/jsset.rs
index 4f521a6637..663cc9b280 100644
--- a/boa_engine/src/object/jsset.rs
+++ b/boa_engine/src/object/jsset.rs
@@ -5,7 +5,7 @@ use boa_gc::{Finalize, Trace};
 use crate::{
     builtins::Set,
     object::{JsFunction, JsObject, JsObjectType, JsSetIterator},
-    Context, JsResult, JsValue,
+    Context, JsResult, JsValue, value::JsVariant,
 };
 
 // This is an wrapper for `JsSet`
@@ -61,7 +61,7 @@ impl JsSet {
     /// Same as JavaScript's `set.clear()`.
     #[inline]
     pub fn clear(&self, context: &mut Context) -> JsResult<JsValue> {
-        Set::clear(&self.inner.clone().into(), &[JsValue::Null], context)
+        Set::clear(&self.inner.clone().into(), &[JsValue::null()], context)
     }
 
     /// Removes the element associated to the value.
@@ -74,9 +74,9 @@ impl JsSet {
     where
         T: Into<JsValue>,
     {
-        match Set::delete(&self.inner.clone().into(), &[value.into()], context)? {
-            JsValue::Boolean(bool) => Ok(bool),
-            _ => Err(JsValue::Undefined),
+        match Set::delete(&self.inner.clone().into(), &[value.into()], context)?.variant() {
+            JsVariant::Boolean(bool) => Ok(bool),
+            _ => Err(JsValue::undefined()),
         }
     }
 
@@ -89,9 +89,9 @@ impl JsSet {
     where
         T: Into<JsValue>,
     {
-        match Set::has(&self.inner.clone().into(), &[value.into()], context)? {
-            JsValue::Boolean(bool) => Ok(bool),
-            _ => Err(JsValue::Undefined),
+        match Set::has(&self.inner.clone().into(), &[value.into()], context)?.variant()  {
+            JsVariant::Boolean(bool) => Ok(bool),
+            _ => Err(JsValue::undefined()),
         }
     }
 
@@ -101,7 +101,7 @@ impl JsSet {
     /// Same as JavaScript's `set.values()`.
     #[inline]
     pub fn values(&self, context: &mut Context) -> JsResult<JsSetIterator> {
-        let iterator_object = Set::values(&self.inner.clone().into(), &[JsValue::Null], context)?
+        let iterator_object = Set::values(&self.inner.clone().into(), &[JsValue::null()], context)?
             .get_iterator(context, None, None)?;
 
         JsSetIterator::from_object(iterator_object.iterator().clone(), context)
@@ -114,7 +114,7 @@ impl JsSet {
     /// Same as JavaScript's `set.keys()`.
     #[inline]
     pub fn keys(&self, context: &mut Context) -> JsResult<JsSetIterator> {
-        let iterator_object = Set::values(&self.inner.clone().into(), &[JsValue::Null], context)?
+        let iterator_object = Set::values(&self.inner.clone().into(), &[JsValue::null()], context)?
             .get_iterator(context, None, None)?;
 
         JsSetIterator::from_object(iterator_object.iterator().clone(), context)
diff --git a/boa_engine/src/object/jsset_iterator.rs b/boa_engine/src/object/jsset_iterator.rs
index 64f06ad0f8..ddd30a3ba5 100644
--- a/boa_engine/src/object/jsset_iterator.rs
+++ b/boa_engine/src/object/jsset_iterator.rs
@@ -26,7 +26,7 @@ impl JsSetIterator {
     }
     /// Advances the `JsSetIterator` and gets the next result in the `JsSet`.
     pub fn next(&self, context: &mut Context) -> JsResult<JsValue> {
-        SetIterator::next(&self.inner.clone().into(), &[JsValue::Null], context)
+        SetIterator::next(&self.inner.clone().into(), &[JsValue::null()], context)
     }
 }
 
diff --git a/boa_engine/src/object/jstypedarray.rs b/boa_engine/src/object/jstypedarray.rs
index 6fb5bc60bf..13e29ed512 100644
--- a/boa_engine/src/object/jstypedarray.rs
+++ b/boa_engine/src/object/jstypedarray.rs
@@ -10,7 +10,7 @@ use std::ops::Deref;
 /// JavaScript `TypedArray` rust object.
 #[derive(Debug, Clone, Trace, Finalize)]
 pub struct JsTypedArray {
-    inner: JsValue,
+    inner: JsObject,
 }
 
 impl JsTypedArray {
@@ -20,9 +20,7 @@ impl JsTypedArray {
     #[inline]
     pub fn from_object(object: JsObject, context: &mut Context) -> JsResult<Self> {
         if object.borrow().is_typed_array() {
-            Ok(Self {
-                inner: object.into(),
-            })
+            Ok(Self { inner: object })
         } else {
             context.throw_type_error("object is not a TypedArray")
         }
@@ -33,7 +31,7 @@ impl JsTypedArray {
     /// Same a `array.length` in JavaScript.
     #[inline]
     pub fn length(&self, context: &mut Context) -> JsResult<usize> {
-        Ok(TypedArray::length(&self.inner, &[], context)?
+        Ok(TypedArray::length(&self.clone().into(), &[], context)?
             .as_number()
             .map(|x| x as usize)
             .expect("length should return a number"))
@@ -50,12 +48,12 @@ impl JsTypedArray {
     where
         T: Into<i64>,
     {
-        TypedArray::at(&self.inner, &[index.into().into()], context)
+        TypedArray::at(&self.clone().into(), &[index.into().into()], context)
     }
 
     #[inline]
     pub fn byte_length(&self, context: &mut Context) -> JsResult<usize> {
-        Ok(TypedArray::byte_length(&self.inner, &[], context)?
+        Ok(TypedArray::byte_length(&self.clone().into(), &[], context)?
             .as_number()
             .map(|x| x as usize)
             .expect("byteLength should return a number"))
@@ -63,7 +61,7 @@ impl JsTypedArray {
 
     #[inline]
     pub fn byte_offset(&self, context: &mut Context) -> JsResult<usize> {
-        Ok(TypedArray::byte_offset(&self.inner, &[], context)?
+        Ok(TypedArray::byte_offset(&self.clone().into(), &[], context)?
             .as_number()
             .map(|x| x as usize)
             .expect("byteLength should return a number"))
@@ -81,7 +79,7 @@ impl JsTypedArray {
         T: Into<JsValue>,
     {
         TypedArray::fill(
-            &self.inner,
+            &self.clone().into(),
             &[
                 value.into(),
                 start.into_or_undefined(),
@@ -99,7 +97,7 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<bool> {
         let result = TypedArray::every(
-            &self.inner,
+            &self.clone().into(),
             &[predicate.into(), this_arg.into_or_undefined()],
             context,
         )?
@@ -117,7 +115,7 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<bool> {
         let result = TypedArray::some(
-            &self.inner,
+            &self.clone().into(),
             &[callback.into(), this_arg.into_or_undefined()],
             context,
         )?
@@ -129,7 +127,11 @@ impl JsTypedArray {
 
     #[inline]
     pub fn sort(&self, compare_fn: Option<JsFunction>, context: &mut Context) -> JsResult<Self> {
-        TypedArray::sort(&self.inner, &[compare_fn.into_or_undefined()], context)?;
+        TypedArray::sort(
+            &self.clone().into(),
+            &[compare_fn.into_or_undefined()],
+            context,
+        )?;
 
         Ok(self.clone())
     }
@@ -142,10 +144,14 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<Self> {
         let object = TypedArray::filter(
-            &self.inner,
+            &self.clone().into(),
             &[callback.into(), this_arg.into_or_undefined()],
             context,
-        )?;
+        )?
+        .as_object()
+        .as_deref()
+        .cloned()
+        .expect("Filter must always return an array object on success");
 
         Ok(Self { inner: object })
     }
@@ -158,10 +164,14 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<Self> {
         let object = TypedArray::map(
-            &self.inner,
+            &self.clone().into(),
             &[callback.into(), this_arg.into_or_undefined()],
             context,
-        )?;
+        )?
+        .as_object()
+        .as_deref()
+        .cloned()
+        .expect("Filter must always return an array object on success");
 
         Ok(Self { inner: object })
     }
@@ -174,7 +184,7 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<JsValue> {
         TypedArray::reduce(
-            &self.inner,
+            &self.clone().into(),
             &[callback.into(), initial_value.into_or_undefined()],
             context,
         )
@@ -188,7 +198,7 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<JsValue> {
         TypedArray::reduceright(
-            &self.inner,
+            &self.clone().into(),
             &[callback.into(), initial_value.into_or_undefined()],
             context,
         )
@@ -196,7 +206,7 @@ impl JsTypedArray {
 
     #[inline]
     pub fn reverse(&self, context: &mut Context) -> JsResult<Self> {
-        TypedArray::reverse(&self.inner, &[], context)?;
+        TypedArray::reverse(&self.clone().into(), &[], context)?;
         Ok(self.clone())
     }
 
@@ -208,10 +218,14 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<Self> {
         let object = TypedArray::slice(
-            &self.inner,
+            &self.clone().into(),
             &[start.into_or_undefined(), end.into_or_undefined()],
             context,
-        )?;
+        )?
+        .as_object()
+        .as_deref()
+        .cloned()
+        .expect("Filter must always return an array object on success");
 
         Ok(Self { inner: object })
     }
@@ -224,7 +238,7 @@ impl JsTypedArray {
         context: &mut Context,
     ) -> JsResult<JsValue> {
         TypedArray::find(
-            &self.inner,
+            &self.clone().into(),
             &[predicate.into(), this_arg.into_or_undefined()],
             context,
         )
@@ -241,7 +255,7 @@ impl JsTypedArray {
         T: Into<JsValue>,
     {
         let index = TypedArray::index_of(
-            &self.inner,
+            &self.clone().into(),
             &[search_element.into(), from_index.into_or_undefined()],
             context,
         )?
@@ -267,7 +281,7 @@ impl JsTypedArray {
         T: Into<JsValue>,
     {
         let index = TypedArray::last_index_of(
-            &self.inner,
+            &self.clone().into(),
             &[search_element.into(), from_index.into_or_undefined()],
             context,
         )?
@@ -284,8 +298,14 @@ impl JsTypedArray {
 
     #[inline]
     pub fn join(&self, separator: Option<JsString>, context: &mut Context) -> JsResult<JsString> {
-        TypedArray::join(&self.inner, &[separator.into_or_undefined()], context).map(|x| {
+        TypedArray::join(
+            &self.clone().into(),
+            &[separator.into_or_undefined()],
+            context,
+        )
+        .map(|x| {
             x.as_string()
+                .as_deref()
                 .cloned()
                 .expect("TypedArray.prototype.join always returns string")
         })
@@ -295,17 +315,14 @@ impl JsTypedArray {
 impl From<JsTypedArray> for JsObject {
     #[inline]
     fn from(o: JsTypedArray) -> Self {
-        o.inner
-            .as_object()
-            .expect("should always be an object")
-            .clone()
+        o.inner.clone()
     }
 }
 
 impl From<JsTypedArray> for JsValue {
     #[inline]
     fn from(o: JsTypedArray) -> Self {
-        o.inner.clone()
+        o.inner.clone().into()
     }
 }
 
@@ -314,7 +331,7 @@ impl Deref for JsTypedArray {
 
     #[inline]
     fn deref(&self) -> &Self::Target {
-        self.inner.as_object().expect("should always be an object")
+        &self.inner
     }
 }
 
@@ -392,18 +409,14 @@ macro_rules! JsTypedArrayType {
         impl From<$name> for JsObject {
             #[inline]
             fn from(o: $name) -> Self {
-                o.inner
-                    .inner
-                    .as_object()
-                    .expect("should always be an object")
-                    .clone()
+                o.inner.inner.clone()
             }
         }
 
         impl From<$name> for JsValue {
             #[inline]
             fn from(o: $name) -> Self {
-                o.inner.inner.clone()
+                o.inner.inner.clone().into()
             }
         }
 
diff --git a/boa_engine/src/object/operations.rs b/boa_engine/src/object/operations.rs
index 85d852edec..dc76b1744d 100644
--- a/boa_engine/src/object/operations.rs
+++ b/boa_engine/src/object/operations.rs
@@ -4,7 +4,7 @@ use crate::{
     object::JsObject,
     property::{PropertyDescriptor, PropertyDescriptorBuilder, PropertyKey, PropertyNameKind},
     symbol::WellKnownSymbols,
-    value::Type,
+    value::{JsVariant, Type},
     Context, JsResult, JsValue,
 };
 
@@ -594,11 +594,14 @@ impl JsObject {
 
         // 1. Assert: IsPropertyKey(P) is true.
         // 2. Let func be ? GetV(V, P).
-        match &self.__get__(&key.into(), self.clone().into(), context)? {
+        match self
+            .__get__(&key.into(), self.clone().into(), context)?
+            .variant()
+        {
             // 3. If func is either undefined or null, return undefined.
-            JsValue::Undefined | JsValue::Null => Ok(None),
+            JsVariant::Undefined | JsVariant::Null => Ok(None),
             // 5. Return func.
-            JsValue::Object(obj) if obj.is_callable() => Ok(Some(obj.clone())),
+            JsVariant::Object(object) if object.is_callable() => Ok(Some(object.clone())),
             // 4. If IsCallable(func) is false, throw a TypeError exception.
             _ => {
                 context.throw_type_error("value returned for property of object is not a function")
@@ -833,7 +836,7 @@ impl JsValue {
             };
 
             // c. If SameValue(P, O) is true, return true.
-            if JsObject::equals(&object, prototype) {
+            if JsObject::equals(&object, &prototype) {
                 return Ok(true);
             }
         }
diff --git a/boa_engine/src/string.rs b/boa_engine/src/string.rs
index b8c76e631c..de2f5354c8 100644
--- a/boa_engine/src/string.rs
+++ b/boa_engine/src/string.rs
@@ -1,4 +1,4 @@
-use crate::builtins::string::is_trimmable_whitespace;
+use crate::{builtins::string::is_trimmable_whitespace, value::PointerType};
 use boa_gc::{unsafe_empty_trace, Finalize, Trace};
 use rustc_hash::{FxHashMap, FxHasher};
 use std::{
@@ -8,6 +8,7 @@ use std::{
     hash::BuildHasherDefault,
     hash::{Hash, Hasher},
     marker::PhantomData,
+    mem::ManuallyDrop,
     ops::Deref,
     ptr::{copy_nonoverlapping, NonNull},
     rc::Rc,
@@ -635,12 +636,26 @@ pub struct JsString {
     _marker: PhantomData<Rc<str>>,
 }
 
+unsafe impl PointerType for JsString {
+    unsafe fn from_void_ptr(ptr: *mut ()) -> ManuallyDrop<Self> {
+        let string = Self {
+            inner: TaggedInner(NonNull::new_unchecked(ptr.cast())),
+            _marker: PhantomData,
+        };
+
+        ManuallyDrop::new(string)
+    }
+
+    unsafe fn into_void_ptr(string: ManuallyDrop<Self>) -> *mut () {
+        string.inner.0.as_ptr().cast()
+    }
+}
+
 // Safety: JsString does not contain any objects which needs to be traced,
 // so this is safe.
 unsafe impl Trace for JsString {
     unsafe_empty_trace!();
 }
-
 /// This struct uses a technique called tagged pointer to benefit from the fact that newly
 /// allocated pointers are always word aligned on 64-bits platforms, making it impossible
 /// to have a LSB equal to 1. More details about this technique on the article of Wikipedia
diff --git a/boa_engine/src/symbol.rs b/boa_engine/src/symbol.rs
index bbd013978f..3c13f359c2 100644
--- a/boa_engine/src/symbol.rs
+++ b/boa_engine/src/symbol.rs
@@ -15,12 +15,13 @@
 //! [spec]: https://tc39.es/ecma262/#sec-symbol-value
 //! [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol
 
-use crate::JsString;
+use crate::{value::PointerType, JsString};
 use boa_gc::{unsafe_empty_trace, Finalize, Trace};
 use std::{
     cell::Cell,
     fmt::{self, Display},
     hash::{Hash, Hasher},
+    mem::{self, ManuallyDrop},
     rc::Rc,
 };
 
@@ -253,12 +254,23 @@ pub struct JsSymbol {
     inner: Rc<Inner>,
 }
 
+unsafe impl PointerType for JsSymbol {
+    unsafe fn from_void_ptr(ptr: *mut ()) -> ManuallyDrop<Self> {
+        ManuallyDrop::new(mem::transmute(ptr))
+    }
+
+    unsafe fn into_void_ptr(symbol: ManuallyDrop<Self>) -> *mut () {
+        mem::transmute(symbol)
+    }
+}
+
 // Safety: JsSymbol does not contain any objects which needs to be traced,
 // so this is safe.
 unsafe impl Trace for JsSymbol {
     unsafe_empty_trace!();
 }
 
+
 impl JsSymbol {
     /// Create a new symbol.
     #[inline]
diff --git a/boa_engine/src/tests.rs b/boa_engine/src/tests.rs
index 24cbb02005..0486cf89bc 100644
--- a/boa_engine/src/tests.rs
+++ b/boa_engine/src/tests.rs
@@ -874,6 +874,7 @@ mod in_operator {
                 .get("prototype", &mut context)
                 .unwrap()
                 .as_object()
+                .as_deref()
                 .cloned())
         );
     }
@@ -1057,7 +1058,7 @@ fn to_integer_or_infinity() {
 fn to_length() {
     let mut context = Context::default();
 
-    assert_eq!(JsValue::new(f64::NAN).to_length(&mut context).unwrap(), 0);
+    assert_eq!(JsValue::nan().to_length(&mut context).unwrap(), 0);
     assert_eq!(
         JsValue::new(f64::NEG_INFINITY)
             .to_length(&mut context)
diff --git a/boa_engine/src/value/conversions.rs b/boa_engine/src/value/conversions.rs
index 771acbbf8c..ae3c63e54e 100644
--- a/boa_engine/src/value/conversions.rs
+++ b/boa_engine/src/value/conversions.rs
@@ -1,4 +1,8 @@
-use super::{Display, JsBigInt, JsObject, JsString, JsSymbol, JsValue, Profiler};
+use boa_profiler::Profiler;
+
+use crate::{object::JsObject, JsBigInt, JsString, JsSymbol};
+
+use super::{Display, JsValue};
 
 impl From<&Self> for JsValue {
     #[inline]
@@ -15,7 +19,7 @@ where
     fn from(value: T) -> Self {
         let _timer = Profiler::global().start_event("From<String>", "value");
 
-        Self::String(value.into())
+        Self::string(value.into())
     }
 }
 
@@ -29,16 +33,7 @@ impl From<char> for JsValue {
 impl From<JsSymbol> for JsValue {
     #[inline]
     fn from(value: JsSymbol) -> Self {
-        Self::Symbol(value)
-    }
-}
-
-#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
-pub struct TryFromCharError;
-
-impl Display for TryFromCharError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "Could not convert value to a char type")
+        Self::symbol(value)
     }
 }
 
@@ -49,7 +44,7 @@ impl From<f32> for JsValue {
         // if value as i32 as f64 == value {
         //     Self::Integer(value as i32)
         // } else {
-        Self::Rational(value.into())
+        Self::float64(value.into())
         // }
     }
 }
@@ -61,7 +56,7 @@ impl From<f64> for JsValue {
         // if value as i32 as f64 == value {
         //     Self::Integer(value as i32)
         // } else {
-        Self::Rational(value)
+        Self::float64(value)
         // }
     }
 }
@@ -69,28 +64,28 @@ impl From<f64> for JsValue {
 impl From<u8> for JsValue {
     #[inline]
     fn from(value: u8) -> Self {
-        Self::Integer(value.into())
+        Self::integer32(value.into())
     }
 }
 
 impl From<i8> for JsValue {
     #[inline]
     fn from(value: i8) -> Self {
-        Self::Integer(value.into())
+        Self::integer32(value.into())
     }
 }
 
 impl From<u16> for JsValue {
     #[inline]
     fn from(value: u16) -> Self {
-        Self::Integer(value.into())
+        Self::integer32(value.into())
     }
 }
 
 impl From<i16> for JsValue {
     #[inline]
     fn from(value: i16) -> Self {
-        Self::Integer(value.into())
+        Self::integer32(value.into())
     }
 }
 
@@ -98,9 +93,9 @@ impl From<u32> for JsValue {
     #[inline]
     fn from(value: u32) -> Self {
         if let Ok(integer) = i32::try_from(value) {
-            Self::Integer(integer)
+            Self::integer32(integer)
         } else {
-            Self::Rational(value.into())
+            Self::float64(value.into())
         }
     }
 }
@@ -108,14 +103,14 @@ impl From<u32> for JsValue {
 impl From<i32> for JsValue {
     #[inline]
     fn from(value: i32) -> Self {
-        Self::Integer(value)
+        Self::integer32(value)
     }
 }
 
 impl From<JsBigInt> for JsValue {
     #[inline]
     fn from(value: JsBigInt) -> Self {
-        Self::BigInt(value)
+        Self::bigint(value)
     }
 }
 
@@ -123,9 +118,9 @@ impl From<usize> for JsValue {
     #[inline]
     fn from(value: usize) -> Self {
         if let Ok(value) = i32::try_from(value) {
-            Self::Integer(value)
+            Self::integer32(value)
         } else {
-            Self::Rational(value as f64)
+            Self::float64(value as f64)
         }
     }
 }
@@ -134,9 +129,9 @@ impl From<u64> for JsValue {
     #[inline]
     fn from(value: u64) -> Self {
         if let Ok(value) = i32::try_from(value) {
-            Self::Integer(value)
+            Self::integer32(value)
         } else {
-            Self::Rational(value as f64)
+            Self::float64(value as f64)
         }
     }
 }
@@ -145,9 +140,9 @@ impl From<i64> for JsValue {
     #[inline]
     fn from(value: i64) -> Self {
         if let Ok(value) = i32::try_from(value) {
-            Self::Integer(value)
+            Self::integer32(value)
         } else {
-            Self::Rational(value as f64)
+            Self::float64(value as f64)
         }
     }
 }
@@ -155,7 +150,7 @@ impl From<i64> for JsValue {
 impl From<bool> for JsValue {
     #[inline]
     fn from(value: bool) -> Self {
-        Self::Boolean(value)
+        Self::boolean(value)
     }
 }
 
@@ -163,7 +158,7 @@ impl From<JsObject> for JsValue {
     #[inline]
     fn from(object: JsObject) -> Self {
         let _timer = Profiler::global().start_event("From<JsObject>", "value");
-        Self::Object(object)
+        Self::object(object)
     }
 }
 
@@ -174,6 +169,25 @@ impl From<()> for JsValue {
     }
 }
 
+#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
+pub struct TryFromObjectError;
+
+impl Display for TryFromObjectError {
+    #[inline]
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Could not convert value to an Object type")
+    }
+}
+
+#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
+pub struct TryFromCharError;
+
+impl Display for TryFromCharError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Could not convert value to a char type")
+    }
+}
+
 pub(crate) trait IntoOrUndefined {
     fn into_or_undefined(self) -> JsValue;
 }
@@ -183,6 +197,6 @@ where
     T: Into<JsValue>,
 {
     fn into_or_undefined(self) -> JsValue {
-        self.map_or_else(JsValue::undefined, Into::into)
+        self.map_or(JsValue::undefined(), Into::into)
     }
 }
diff --git a/boa_engine/src/value/display.rs b/boa_engine/src/value/display.rs
index 5430cc09bb..1d7cb6d395 100644
--- a/boa_engine/src/value/display.rs
+++ b/boa_engine/src/value/display.rs
@@ -1,6 +1,6 @@
 use crate::{object::ObjectKind, property::PropertyDescriptor};
 
-use super::{fmt, Display, HashSet, JsValue, PropertyKey};
+use super::{fmt, Display, HashSet, JsValue, JsVariant, PropertyKey};
 
 /// This object is used for displaying a `Value`.
 #[derive(Debug, Clone, Copy)]
@@ -55,7 +55,7 @@ macro_rules! print_obj_value {
                 vec![format!(
                     "{:>width$}: {}",
                     "__proto__",
-                    JsValue::Null.display(),
+                    JsValue::null().display(),
                     width = $indent,
                 )]
             }
@@ -96,9 +96,9 @@ macro_rules! print_obj_value {
 }
 
 pub(crate) fn log_string_from(x: &JsValue, print_internals: bool, print_children: bool) -> String {
-    match x {
+    match x.variant() {
         // We don't want to print private (compiler) or prototype properties
-        JsValue::Object(ref v) => {
+        JsVariant::Object(v) => {
             // Can use the private "type" field of an Object to match on
             // which type of Object it represents for special printing
             match v.borrow().kind() {
@@ -196,7 +196,7 @@ pub(crate) fn log_string_from(x: &JsValue, print_internals: bool, print_children
                 _ => display_obj(x, print_internals),
             }
         }
-        JsValue::Symbol(ref symbol) => symbol.to_string(),
+        JsVariant::Symbol(ref symbol) => symbol.to_string(),
         _ => x.display().to_string(),
     }
 }
@@ -216,7 +216,7 @@ pub(crate) fn display_obj(v: &JsValue, print_internals: bool) -> String {
         indent: usize,
         print_internals: bool,
     ) -> String {
-        if let JsValue::Object(ref v) = *data {
+        if let Some(v) = data.as_object() {
             // The in-memory address of the current object
             let addr = address_of(v.as_ref());
 
@@ -254,20 +254,20 @@ pub(crate) fn display_obj(v: &JsValue, print_internals: bool) -> String {
     // in-memory address in this set
     let mut encounters = HashSet::new();
 
-    if let JsValue::Object(object) = v {
+    if let Some(object) = v.as_object() {
         if object.borrow().is_error() {
             let name = v
                 .get_property("name")
                 .as_ref()
                 .and_then(PropertyDescriptor::value)
-                .unwrap_or(&JsValue::Undefined)
+                .unwrap_or(&JsValue::undefined())
                 .display()
                 .to_string();
             let message = v
                 .get_property("message")
                 .as_ref()
                 .and_then(PropertyDescriptor::value)
-                .unwrap_or(&JsValue::Undefined)
+                .unwrap_or(&JsValue::undefined())
                 .display()
                 .to_string();
             return format!("{name}: {message}");
@@ -279,21 +279,21 @@ pub(crate) fn display_obj(v: &JsValue, print_internals: bool) -> String {
 
 impl Display for ValueDisplay<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.value {
-            JsValue::Null => write!(f, "null"),
-            JsValue::Undefined => write!(f, "undefined"),
-            JsValue::Boolean(v) => write!(f, "{v}"),
-            JsValue::Symbol(ref symbol) => match symbol.description() {
+        match self.value.variant() {
+            JsVariant::Null => write!(f, "null"),
+            JsVariant::Undefined => write!(f, "undefined"),
+            JsVariant::Boolean(v) => write!(f, "{v}"),
+            JsVariant::Symbol(symbol) => match symbol.description() {
                 Some(description) => write!(f, "Symbol({description})"),
                 None => write!(f, "Symbol()"),
             },
-            JsValue::String(ref v) => write!(f, "\"{v}\""),
-            JsValue::Rational(v) => format_rational(*v, f),
-            JsValue::Object(_) => {
+            JsVariant::String(v) => write!(f, "\"{}\"", *v),
+            JsVariant::Float64(v) => format_rational(v, f),
+            JsVariant::Object(_) => {
                 write!(f, "{}", log_string_from(self.value, self.internals, true))
             }
-            JsValue::Integer(v) => write!(f, "{v}"),
-            JsValue::BigInt(ref num) => write!(f, "{num}n"),
+            JsVariant::Integer32(v) => write!(f, "{v}"),
+            JsVariant::BigInt(num) => write!(f, "{}n", *num),
         }
     }
 }
diff --git a/boa_engine/src/value/equality.rs b/boa_engine/src/value/equality.rs
index c7d4d65235..c4ce3787f6 100644
--- a/boa_engine/src/value/equality.rs
+++ b/boa_engine/src/value/equality.rs
@@ -1,4 +1,4 @@
-use super::{JsBigInt, JsObject, JsResult, JsValue, PreferredType};
+use super::{JsBigInt, JsObject, JsResult, JsValue, JsVariant, PreferredType};
 use crate::{builtins::Number, Context};
 
 impl JsValue {
@@ -12,20 +12,20 @@ impl JsValue {
             return false;
         }
 
-        match (self, other) {
+        match (self.variant(), other.variant()) {
             // 2. If Type(x) is Number or BigInt, then
             //    a. Return ! Type(x)::equal(x, y).
-            (Self::BigInt(x), Self::BigInt(y)) => JsBigInt::equal(x, y),
-            (Self::Rational(x), Self::Rational(y)) => Number::equal(*x, *y),
-            (Self::Rational(x), Self::Integer(y)) => Number::equal(*x, f64::from(*y)),
-            (Self::Integer(x), Self::Rational(y)) => Number::equal(f64::from(*x), *y),
-            (Self::Integer(x), Self::Integer(y)) => x == y,
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => JsBigInt::equal(x, y),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Number::equal(x, y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Number::equal(x, f64::from(y)),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Number::equal(f64::from(x), y),
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => x == y,
 
             //Null has to be handled specially because "typeof null" returns object and if we managed
             //this without a special case we would compare self and other as if they were actually
             //objects which unfortunately fails
             //Specification Link: https://tc39.es/ecma262/#sec-typeof-operator
-            (Self::Null, Self::Null) => true,
+            (JsVariant::Null, JsVariant::Null) => true,
 
             // 3. Return ! SameValueNonNumeric(x, y).
             (_, _) => Self::same_value_non_numeric(self, other),
@@ -44,17 +44,22 @@ impl JsValue {
             return Ok(self.strict_equals(other));
         }
 
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // 2. If x is null and y is undefined, return true.
             // 3. If x is undefined and y is null, return true.
-            (Self::Null, Self::Undefined) | (Self::Undefined, Self::Null) => true,
+            (JsVariant::Null, JsVariant::Undefined) | (JsVariant::Undefined, JsVariant::Null) => {
+                true
+            }
 
             // 3. If Type(x) is Number and Type(y) is String, return the result of the comparison x == ! ToNumber(y).
             // 4. If Type(x) is String and Type(y) is Number, return the result of the comparison ! ToNumber(x) == y.
             //
             // https://github.com/rust-lang/rust/issues/54883
-            (Self::Integer(_) | Self::Rational(_), Self::String(_) | Self::Boolean(_))
-            | (Self::String(_), Self::Integer(_) | Self::Rational(_)) => {
+            (
+                JsVariant::Integer32(_) | JsVariant::Float64(_),
+                JsVariant::String(_) | JsVariant::Boolean(_),
+            )
+            | (JsVariant::String(_), JsVariant::Integer32(_) | JsVariant::Float64(_)) => {
                 let x = self.to_number(context)?;
                 let y = other.to_number(context)?;
                 Number::equal(x, y)
@@ -64,32 +69,32 @@ impl JsValue {
             //    a. Let n be ! StringToBigInt(y).
             //    b. If n is NaN, return false.
             //    c. Return the result of the comparison x == n.
-            (Self::BigInt(ref a), Self::String(ref b)) => match JsBigInt::from_string(b) {
-                Some(ref b) => a == b,
+            (JsVariant::BigInt(a), JsVariant::String(ref b)) => match JsBigInt::from_string(b) {
+                Some(b) => *a == b,
                 None => false,
             },
 
             // 7. If Type(x) is String and Type(y) is BigInt, return the result of the comparison y == x.
-            (Self::String(ref a), Self::BigInt(ref b)) => match JsBigInt::from_string(a) {
-                Some(ref a) => a == b,
+            (JsVariant::String(ref a), JsVariant::BigInt(b)) => match JsBigInt::from_string(a) {
+                Some(a) => a == *b,
                 None => false,
             },
 
             // 8. If Type(x) is Boolean, return the result of the comparison ! ToNumber(x) == y.
-            (Self::Boolean(x), _) => return other.equals(&Self::new(i32::from(*x)), context),
+            (JsVariant::Boolean(x), _) => return other.equals(&Self::new(i32::from(x)), context),
 
             // 9. If Type(y) is Boolean, return the result of the comparison x == ! ToNumber(y).
-            (_, Self::Boolean(y)) => return self.equals(&Self::new(i32::from(*y)), context),
+            (_, JsVariant::Boolean(y)) => return self.equals(&Self::new(i32::from(y)), context),
 
             // 10. If Type(x) is either String, Number, BigInt, or Symbol and Type(y) is Object, return the result
             // of the comparison x == ? ToPrimitive(y).
             (
-                Self::Object(_),
-                Self::String(_)
-                | Self::Rational(_)
-                | Self::Integer(_)
-                | Self::BigInt(_)
-                | Self::Symbol(_),
+                JsVariant::Object(_),
+                JsVariant::String(_)
+                | JsVariant::Float64(_)
+                | JsVariant::Integer32(_)
+                | JsVariant::BigInt(_)
+                | JsVariant::Symbol(_),
             ) => {
                 let primitive = self.to_primitive(context, PreferredType::Default)?;
                 return Ok(primitive
@@ -100,12 +105,12 @@ impl JsValue {
             // 11. If Type(x) is Object and Type(y) is either String, Number, BigInt, or Symbol, return the result
             // of the comparison ? ToPrimitive(x) == y.
             (
-                Self::String(_)
-                | Self::Rational(_)
-                | Self::Integer(_)
-                | Self::BigInt(_)
-                | Self::Symbol(_),
-                Self::Object(_),
+                JsVariant::String(_)
+                | JsVariant::Float64(_)
+                | JsVariant::Integer32(_)
+                | JsVariant::BigInt(_)
+                | JsVariant::Symbol(_),
+                JsVariant::Object(_),
             ) => {
                 let primitive = other.to_primitive(context, PreferredType::Default)?;
                 return Ok(primitive
@@ -116,10 +121,10 @@ impl JsValue {
             // 12. If Type(x) is BigInt and Type(y) is Number, or if Type(x) is Number and Type(y) is BigInt, then
             //    a. If x or y are any of NaN, +∞, or -∞, return false.
             //    b. If the mathematical value of x is equal to the mathematical value of y, return true; otherwise return false.
-            (Self::BigInt(ref a), Self::Rational(ref b)) => a == b,
-            (Self::Rational(ref a), Self::BigInt(ref b)) => a == b,
-            (Self::BigInt(ref a), Self::Integer(ref b)) => a == b,
-            (Self::Integer(ref a), Self::BigInt(ref b)) => a == b,
+            (JsVariant::BigInt(a), JsVariant::Float64(b)) => *a == b,
+            (JsVariant::Float64(a), JsVariant::BigInt(b)) => a == *b,
+            (JsVariant::BigInt(a), JsVariant::Integer32(b)) => *a == b,
+            (JsVariant::Integer32(a), JsVariant::BigInt(b)) => a == *b,
 
             // 13. Return false.
             _ => false,
@@ -139,14 +144,14 @@ impl JsValue {
             return false;
         }
 
-        match (x, y) {
+        match (x.variant(), y.variant()) {
             // 2. If Type(x) is Number or BigInt, then
             //    a. Return ! Type(x)::SameValue(x, y).
-            (Self::BigInt(x), Self::BigInt(y)) => JsBigInt::same_value(x, y),
-            (Self::Rational(x), Self::Rational(y)) => Number::same_value(*x, *y),
-            (Self::Rational(x), Self::Integer(y)) => Number::same_value(*x, f64::from(*y)),
-            (Self::Integer(x), Self::Rational(y)) => Number::same_value(f64::from(*x), *y),
-            (Self::Integer(x), Self::Integer(y)) => x == y,
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => JsBigInt::same_value(x, y),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Number::same_value(x, y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Number::same_value(x, f64::from(y)),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Number::same_value(f64::from(x), y),
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => x == y,
 
             // 3. Return ! SameValueNonNumeric(x, y).
             (_, _) => Self::same_value_non_numeric(x, y),
@@ -167,19 +172,19 @@ impl JsValue {
             return false;
         }
 
-        match (x, y) {
+        match (x.variant(), y.variant()) {
             // 2. If Type(x) is Number or BigInt, then
             //    a. Return ! Type(x)::SameValueZero(x, y).
-            (JsValue::BigInt(x), JsValue::BigInt(y)) => JsBigInt::same_value_zero(x, y),
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => JsBigInt::same_value_zero(x, y),
 
-            (JsValue::Rational(x), JsValue::Rational(y)) => Number::same_value_zero(*x, *y),
-            (JsValue::Rational(x), JsValue::Integer(y)) => {
-                Number::same_value_zero(*x, f64::from(*y))
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Number::same_value_zero(x, y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => {
+                Number::same_value_zero(x, f64::from(y))
             }
-            (JsValue::Integer(x), JsValue::Rational(y)) => {
-                Number::same_value_zero(f64::from(*x), *y)
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => {
+                Number::same_value_zero(f64::from(x), y)
             }
-            (JsValue::Integer(x), JsValue::Integer(y)) => x == y,
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => x == y,
 
             // 3. Return ! SameValueNonNumeric(x, y).
             (_, _) => Self::same_value_non_numeric(x, y),
@@ -188,12 +193,14 @@ impl JsValue {
 
     fn same_value_non_numeric(x: &Self, y: &Self) -> bool {
         debug_assert!(x.get_type() == y.get_type());
-        match (x, y) {
-            (Self::Null, Self::Null) | (Self::Undefined, Self::Undefined) => true,
-            (Self::String(ref x), Self::String(ref y)) => x == y,
-            (Self::Boolean(x), Self::Boolean(y)) => x == y,
-            (Self::Object(ref x), Self::Object(ref y)) => JsObject::equals(x, y),
-            (Self::Symbol(ref x), Self::Symbol(ref y)) => x == y,
+        match (x.variant(), y.variant()) {
+            (JsVariant::Null, JsVariant::Null) | (JsVariant::Undefined, JsVariant::Undefined) => {
+                true
+            }
+            (JsVariant::String(x), JsVariant::String(y)) => x == y,
+            (JsVariant::Boolean(x), JsVariant::Boolean(y)) => x == y,
+            (JsVariant::Object(ref x), JsVariant::Object(ref y)) => JsObject::equals(x, y),
+            (JsVariant::Symbol(x), JsVariant::Symbol(y)) => x == y,
             _ => false,
         }
     }
diff --git a/boa_engine/src/value/hash.rs b/boa_engine/src/value/hash.rs
index 4498eca035..e6024c75cb 100644
--- a/boa_engine/src/value/hash.rs
+++ b/boa_engine/src/value/hash.rs
@@ -1,4 +1,4 @@
-use super::JsValue;
+use super::{JsValue, JsVariant};
 use crate::builtins::Number;
 use std::hash::{Hash, Hasher};
 
@@ -37,16 +37,16 @@ impl Hash for RationalHashable {
 
 impl Hash for JsValue {
     fn hash<H: Hasher>(&self, state: &mut H) {
-        match self {
-            Self::Undefined => UndefinedHashable.hash(state),
-            Self::Null => NullHashable.hash(state),
-            Self::String(ref string) => string.hash(state),
-            Self::Boolean(boolean) => boolean.hash(state),
-            Self::Integer(integer) => RationalHashable(f64::from(*integer)).hash(state),
-            Self::BigInt(ref bigint) => bigint.hash(state),
-            Self::Rational(rational) => RationalHashable(*rational).hash(state),
-            Self::Symbol(ref symbol) => Hash::hash(symbol, state),
-            Self::Object(ref object) => std::ptr::hash(object.as_ref(), state),
+        match self.variant() {
+            JsVariant::Undefined => UndefinedHashable.hash(state),
+            JsVariant::Null => NullHashable.hash(state),
+            JsVariant::String(string) => string.hash(state),
+            JsVariant::Boolean(boolean) => boolean.hash(state),
+            JsVariant::Integer32(integer) => RationalHashable(f64::from(integer)).hash(state),
+            JsVariant::BigInt(bigint) => bigint.hash(state),
+            JsVariant::Float64(rational) => RationalHashable(rational).hash(state),
+            JsVariant::Symbol(symbol) => Hash::hash(&*symbol, state),
+            JsVariant::Object(object) => std::ptr::hash(object.as_ref(), state),
         }
     }
 }
diff --git a/boa_engine/src/value/mod.rs b/boa_engine/src/value/mod.rs
index d7798c4312..fae8a3a1ca 100644
--- a/boa_engine/src/value/mod.rs
+++ b/boa_engine/src/value/mod.rs
@@ -1,6 +1,27 @@
-//! This module implements the JavaScript Value.
+#![warn(unsafe_op_in_unsafe_fn)]
+//! This module implements the JavaScript [`JsValue`] type.
 //!
-//! Javascript values, utility methods and conversion between Javascript values and Rust values.
+//! [`JsValue`] implements several utility methods and conversions between Javascript
+//! values and Rust values.
+//!
+//! # Notes
+//!
+//! We recommend using [`JsValue::from`], [`JsValue::new`] or the [`Into::into`]
+//! trait if you need to convert from float types ([`f64`], [`f32`]) to [`JsValue`],
+//! since there are some checks implemented that convert float values to signed
+//! integer values when there's no loss of precision involved.
+//!
+//! Alternatively, you can use the [`JsValue::float64`] method if you do need a pure
+//! [`f64`] value. The constructor skips all conversions from [`f64`]s to
+//! [`i32`]s, even if the value can be represented by an [`i32`] without loss of
+//! precision.
+//!
+//! # Alternative implementations
+//!
+//! `boa` right now implements two versions of [`JsValue`]:
+//! - The default implementation using a simple `enum`.
+//! - A NaN-boxed implementation for x86-64 platforms that can be enabled using the `nan_boxing` feature.
+//! The feature flag is ignored on incompatible platforms.
 
 #[cfg(test)]
 mod tests;
@@ -12,10 +33,9 @@ use crate::{
     },
     object::{JsObject, ObjectData},
     property::{PropertyDescriptor, PropertyKey},
-    symbol::{JsSymbol, WellKnownSymbols},
+    symbol::WellKnownSymbols,
     Context, JsBigInt, JsResult, JsString,
 };
-use boa_gc::{custom_trace, Finalize, Trace};
 use boa_profiler::Profiler;
 use num_bigint::BigInt;
 use num_integer::Integer;
@@ -28,6 +48,11 @@ use std::{
     str::FromStr,
 };
 
+mod sys;
+
+#[doc(inline)]
+pub use sys::{JsValue, JsVariant, Ref};
+
 mod conversions;
 pub(crate) mod display;
 mod equality;
@@ -44,6 +69,7 @@ pub use hash::*;
 pub use integer::IntegerOrInfinity;
 pub use operations::*;
 pub use r#type::Type;
+pub(crate) use sys::PointerType;
 
 static TWO_E_64: Lazy<BigInt> = Lazy::new(|| {
     const TWO_E_64: u128 = 2u128.pow(64);
@@ -55,37 +81,6 @@ static TWO_E_63: Lazy<BigInt> = Lazy::new(|| {
     BigInt::from(TWO_E_63)
 });
 
-/// A Javascript value
-#[derive(Finalize, Debug, Clone)]
-pub enum JsValue {
-    /// `null` - A null value, for when a value doesn't exist.
-    Null,
-    /// `undefined` - An undefined value, for when a field or index doesn't exist.
-    Undefined,
-    /// `boolean` - A `true` / `false` value, for if a certain criteria is met.
-    Boolean(bool),
-    /// `String` - A UTF-8 string, such as `"Hello, world"`.
-    String(JsString),
-    /// `Number` - A 64-bit floating point number, such as `3.1415`
-    Rational(f64),
-    /// `Number` - A 32-bit integer, such as `42`.
-    Integer(i32),
-    /// `BigInt` - holds any arbitrary large signed integer.
-    BigInt(JsBigInt),
-    /// `Object` - An object, such as `Math`, represented by a binary tree of string keys to Javascript values.
-    Object(JsObject),
-    /// `Symbol` - A Symbol Primitive type.
-    Symbol(JsSymbol),
-}
-
-unsafe impl Trace for JsValue {
-    custom_trace! {this, {
-        if let Self::Object(o) = this {
-            mark(o);
-        }
-    }}
-}
-
 impl JsValue {
     /// Create a new [`JsValue`].
     #[inline]
@@ -96,48 +91,28 @@ impl JsValue {
         value.into()
     }
 
-    /// Creates a new `undefined` value.
-    #[inline]
-    pub fn undefined() -> Self {
-        Self::Undefined
-    }
-
-    /// Creates a new `null` value.
+    /// Returns true if the value is null or undefined.
     #[inline]
-    pub fn null() -> Self {
-        Self::Null
+    pub fn is_null_or_undefined(&self) -> bool {
+        self.is_null() || self.is_undefined()
     }
 
     /// Creates a new number with `NaN` value.
     #[inline]
     pub fn nan() -> Self {
-        Self::Rational(f64::NAN)
+        Self::new(f64::NAN)
     }
 
     /// Creates a new number with `Infinity` value.
     #[inline]
     pub fn positive_infinity() -> Self {
-        Self::Rational(f64::INFINITY)
+        Self::new(f64::INFINITY)
     }
 
     /// Creates a new number with `-Infinity` value.
     #[inline]
     pub fn negative_infinity() -> Self {
-        Self::Rational(f64::NEG_INFINITY)
-    }
-
-    /// Returns true if the value is an object
-    #[inline]
-    pub fn is_object(&self) -> bool {
-        matches!(self, Self::Object(_))
-    }
-
-    #[inline]
-    pub fn as_object(&self) -> Option<&JsObject> {
-        match *self {
-            Self::Object(ref o) => Some(o),
-            _ => None,
-        }
+        Self::new(f64::NEG_INFINITY)
     }
 
     /// It determines if the value is a callable function with a `[[Call]]` internal method.
@@ -148,143 +123,68 @@ impl JsValue {
     /// [spec]: https://tc39.es/ecma262/#sec-iscallable
     #[inline]
     pub fn is_callable(&self) -> bool {
-        matches!(self, Self::Object(obj) if obj.is_callable())
+        self.as_object()
+            .as_deref()
+            .map_or(false, JsObject::is_callable)
     }
 
     #[inline]
-    pub fn as_callable(&self) -> Option<&JsObject> {
+    pub fn as_callable(&self) -> Option<Ref<'_, JsObject>> {
         self.as_object().filter(|obj| obj.is_callable())
     }
 
     /// Returns true if the value is a constructor object.
     #[inline]
     pub fn is_constructor(&self) -> bool {
-        matches!(self, Self::Object(obj) if obj.is_constructor())
+        self.as_object()
+            .as_deref()
+            .map_or(false, JsObject::is_constructor)
     }
 
     #[inline]
-    pub fn as_constructor(&self) -> Option<&JsObject> {
+    pub fn as_constructor(&self) -> Option<Ref<'_, JsObject>> {
         self.as_object().filter(|obj| obj.is_constructor())
     }
 
     /// Returns true if the value is a promise object.
     #[inline]
     pub fn is_promise(&self) -> bool {
-        matches!(self, Self::Object(obj) if obj.is_promise())
+        self.as_object()
+            .as_deref()
+            .map_or(false, JsObject::is_promise)
     }
 
     #[inline]
-    pub fn as_promise(&self) -> Option<&JsObject> {
+    pub fn as_promise(&self) -> Option<Ref<'_, JsObject>> {
         self.as_object().filter(|obj| obj.is_promise())
     }
 
-    /// Returns true if the value is a symbol.
-    #[inline]
-    pub fn is_symbol(&self) -> bool {
-        matches!(self, Self::Symbol(_))
-    }
-
-    pub fn as_symbol(&self) -> Option<JsSymbol> {
-        match self {
-            Self::Symbol(symbol) => Some(symbol.clone()),
-            _ => None,
-        }
-    }
-
-    /// Returns true if the value is undefined.
-    #[inline]
-    pub fn is_undefined(&self) -> bool {
-        matches!(self, Self::Undefined)
-    }
-
-    /// Returns true if the value is null.
-    #[inline]
-    pub fn is_null(&self) -> bool {
-        matches!(self, Self::Null)
-    }
-
-    /// Returns true if the value is null or undefined.
-    #[inline]
-    pub fn is_null_or_undefined(&self) -> bool {
-        matches!(self, Self::Null | Self::Undefined)
-    }
-
-    /// Returns true if the value is a 64-bit floating-point number.
-    #[inline]
-    pub fn is_double(&self) -> bool {
-        matches!(self, Self::Rational(_))
-    }
-
-    /// Returns true if the value is integer.
+    /// Returns true if the value is an integer, even if it's represented by an [`f64`].
     #[inline]
     #[allow(clippy::float_cmp)]
     pub fn is_integer(&self) -> bool {
-        // If it can fit in a i32 and the truncated version is
-        // equal to the original then it is an integer.
-        let is_rational_integer = |n: f64| n == f64::from(n as i32);
-
-        match *self {
-            Self::Integer(_) => true,
-            Self::Rational(n) if is_rational_integer(n) => true,
-            _ => false,
+        if self.is_integer32() {
+            return true;
         }
+
+        self.as_float64()
+            // If it can fit in a i32 and the trucated version is
+            // equal to the original then it is an integer.
+            .map(|num| num == f64::from(num as i32))
+            .unwrap_or_default()
     }
 
     /// Returns true if the value is a number.
     #[inline]
     pub fn is_number(&self) -> bool {
-        matches!(self, Self::Rational(_) | Self::Integer(_))
+        self.is_integer32() || self.is_float64()
     }
 
     #[inline]
     pub fn as_number(&self) -> Option<f64> {
-        match *self {
-            Self::Integer(integer) => Some(integer.into()),
-            Self::Rational(rational) => Some(rational),
-            _ => None,
-        }
-    }
-
-    /// Returns true if the value is a string.
-    #[inline]
-    pub fn is_string(&self) -> bool {
-        matches!(self, Self::String(_))
-    }
-
-    /// Returns the string if the values is a string, otherwise `None`.
-    #[inline]
-    pub fn as_string(&self) -> Option<&JsString> {
-        match self {
-            Self::String(ref string) => Some(string),
-            _ => None,
-        }
-    }
-
-    /// Returns true if the value is a boolean.
-    #[inline]
-    pub fn is_boolean(&self) -> bool {
-        matches!(self, Self::Boolean(_))
-    }
-
-    #[inline]
-    pub fn as_boolean(&self) -> Option<bool> {
-        match self {
-            Self::Boolean(boolean) => Some(*boolean),
-            _ => None,
-        }
-    }
-
-    /// Returns true if the value is a bigint.
-    #[inline]
-    pub fn is_bigint(&self) -> bool {
-        matches!(self, Self::BigInt(_))
-    }
-
-    /// Returns an optional reference to a `BigInt` if the value is a `BigInt` primitive.
-    #[inline]
-    pub fn as_bigint(&self) -> Option<&JsBigInt> {
-        match self {
-            Self::BigInt(bigint) => Some(bigint),
+        match self.variant() {
+            JsVariant::Integer32(integer) => Some(integer.into()),
+            JsVariant::Float64(rational) => Some(rational),
             _ => None,
         }
     }
@@ -296,13 +196,13 @@ impl JsValue {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-toboolean
     pub fn to_boolean(&self) -> bool {
-        match *self {
-            Self::Symbol(_) | Self::Object(_) => true,
-            Self::String(ref s) if !s.is_empty() => true,
-            Self::Rational(n) if n != 0.0 && !n.is_nan() => true,
-            Self::Integer(n) if n != 0 => true,
-            Self::BigInt(ref n) if !n.is_zero() => true,
-            Self::Boolean(v) => v,
+        match self.variant() {
+            JsVariant::Symbol(_) | JsVariant::Object(_) => true,
+            JsVariant::String(s) if !s.is_empty() => true,
+            JsVariant::Float64(n) if n != 0.0 && !n.is_nan() => true,
+            JsVariant::Integer32(n) if n != 0 => true,
+            JsVariant::BigInt(n) if !n.is_zero() => true,
+            JsVariant::Boolean(v) => v,
             _ => false,
         }
     }
@@ -316,28 +216,27 @@ impl JsValue {
     {
         let key = key.into();
         let _timer = Profiler::global().start_event("Value::get_property", "value");
-        match self {
-            Self::Object(ref object) => {
-                // TODO: had to skip `__get_own_properties__` since we don't have context here
-                let property = object.borrow().properties().get(&key);
-                if property.is_some() {
-                    return property;
-                }
-
-                object
-                    .prototype()
-                    .as_ref()
-                    .map_or(Self::Null, |obj| obj.clone().into())
-                    .get_property(key)
+        if let Some(object) = self.as_object() {
+            // TODO: had to skip `__get_own_properties__` since we don't have context here
+            let property = object.borrow().properties().get(&key);
+            if property.is_some() {
+                return property;
             }
-            _ => None,
+
+            object
+                .prototype()
+                .as_ref()
+                .map_or(Self::null(), |obj| obj.clone().into())
+                .get_property(key)
+        } else {
+            None
         }
     }
 
     /// Set the kind of an object.
     #[inline]
     pub fn set_data(&self, data: ObjectData) {
-        if let Self::Object(ref obj) = *self {
+        if let Some(obj) = self.as_object() {
             obj.borrow_mut().data = data;
         }
     }
@@ -352,9 +251,9 @@ impl JsValue {
     ) -> JsResult<Self> {
         // 1. Assert: input is an ECMAScript language value. (always a value not need to check)
         // 2. If Type(input) is Object, then
-        if self.is_object() {
+        if let Some(object) = self.as_object() {
             // a. Let exoticToPrim be ? GetMethod(input, @@toPrimitive).
-            let exotic_to_prim = self.get_method(WellKnownSymbols::to_primitive(), context)?;
+            let exotic_to_prim = object.get_method(WellKnownSymbols::to_primitive(), context)?;
 
             // b. If exoticToPrim is not undefined, then
             if let Some(exotic_to_prim) = exotic_to_prim {
@@ -388,9 +287,7 @@ impl JsValue {
             };
 
             // d. Return ? OrdinaryToPrimitive(input, preferredType).
-            self.as_object()
-                .expect("self was not an object")
-                .ordinary_to_primitive(context, preferred_type)
+            object.ordinary_to_primitive(context, preferred_type)
         } else {
             // 3. Return input.
             Ok(self.clone())
@@ -404,10 +301,13 @@ impl JsValue {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-tobigint
     pub fn to_bigint(&self, context: &mut Context) -> JsResult<JsBigInt> {
-        match self {
-            Self::Null => context.throw_type_error("cannot convert null to a BigInt"),
-            Self::Undefined => context.throw_type_error("cannot convert undefined to a BigInt"),
-            Self::String(ref string) => {
+        match self.variant() {
+            JsVariant::Null => context.throw_type_error("cannot convert null to a BigInt"),
+            JsVariant::Undefined => {
+                context.throw_type_error("cannot convert undefined to a BigInt")
+            }
+            JsVariant::String(string) => {
+                let string = &*string;
                 if let Some(value) = JsBigInt::from_string(string) {
                     Ok(value)
                 } else {
@@ -416,17 +316,17 @@ impl JsValue {
                     ))
                 }
             }
-            Self::Boolean(true) => Ok(JsBigInt::one()),
-            Self::Boolean(false) => Ok(JsBigInt::zero()),
-            Self::Integer(_) | Self::Rational(_) => {
+            JsVariant::Boolean(true) => Ok(JsBigInt::one()),
+            JsVariant::Boolean(false) => Ok(JsBigInt::zero()),
+            JsVariant::Integer32(_) | JsVariant::Float64(_) => {
                 context.throw_type_error("cannot convert Number to a BigInt")
             }
-            Self::BigInt(b) => Ok(b.clone()),
-            Self::Object(_) => {
+            JsVariant::BigInt(b) => Ok(b.clone()),
+            JsVariant::Object(_) => {
                 let primitive = self.to_primitive(context, PreferredType::Number)?;
                 primitive.to_bigint(context)
             }
-            Self::Symbol(_) => context.throw_type_error("cannot convert Symbol to a BigInt"),
+            JsVariant::Symbol(_) => context.throw_type_error("cannot convert Symbol to a BigInt"),
         }
     }
 
@@ -456,16 +356,16 @@ impl JsValue {
     ///
     /// This function is equivalent to `String(value)` in JavaScript.
     pub fn to_string(&self, context: &mut Context) -> JsResult<JsString> {
-        match self {
-            Self::Null => Ok("null".into()),
-            Self::Undefined => Ok("undefined".into()),
-            Self::Boolean(boolean) => Ok(boolean.to_string().into()),
-            Self::Rational(rational) => Ok(Number::to_native_string(*rational).into()),
-            Self::Integer(integer) => Ok(integer.to_string().into()),
-            Self::String(string) => Ok(string.clone()),
-            Self::Symbol(_) => context.throw_type_error("can't convert symbol to string"),
-            Self::BigInt(ref bigint) => Ok(bigint.to_string().into()),
-            Self::Object(_) => {
+        match self.variant() {
+            JsVariant::Null => Ok("null".into()),
+            JsVariant::Undefined => Ok("undefined".into()),
+            JsVariant::Boolean(boolean) => Ok(boolean.to_string().into()),
+            JsVariant::Float64(rational) => Ok(Number::to_native_string(rational).into()),
+            JsVariant::Integer32(integer) => Ok(integer.to_string().into()),
+            JsVariant::String(string) => Ok(string.clone()),
+            JsVariant::Symbol(_) => context.throw_type_error("can't convert symbol to string"),
+            JsVariant::BigInt(bigint) => Ok(bigint.to_string().into()),
+            JsVariant::Object(_) => {
                 let primitive = self.to_primitive(context, PreferredType::String)?;
                 primitive.to_string(context)
             }
@@ -478,32 +378,32 @@ impl JsValue {
     ///
     /// See: <https://tc39.es/ecma262/#sec-toobject>
     pub fn to_object(&self, context: &mut Context) -> JsResult<JsObject> {
-        match self {
-            Self::Undefined | Self::Null => {
+        match self.variant() {
+            JsVariant::Undefined | JsVariant::Null => {
                 context.throw_type_error("cannot convert 'null' or 'undefined' to object")
             }
-            Self::Boolean(boolean) => {
+            JsVariant::Boolean(boolean) => {
                 let prototype = context.intrinsics().constructors().boolean().prototype();
                 Ok(JsObject::from_proto_and_data(
                     prototype,
-                    ObjectData::boolean(*boolean),
+                    ObjectData::boolean(boolean),
                 ))
             }
-            Self::Integer(integer) => {
+            JsVariant::Integer32(integer) => {
                 let prototype = context.intrinsics().constructors().number().prototype();
                 Ok(JsObject::from_proto_and_data(
                     prototype,
-                    ObjectData::number(f64::from(*integer)),
+                    ObjectData::number(f64::from(integer)),
                 ))
             }
-            Self::Rational(rational) => {
+            JsVariant::Float64(rational) => {
                 let prototype = context.intrinsics().constructors().number().prototype();
                 Ok(JsObject::from_proto_and_data(
                     prototype,
-                    ObjectData::number(*rational),
+                    ObjectData::number(rational),
                 ))
             }
-            Self::String(ref string) => {
+            JsVariant::String(string) => {
                 let prototype = context.intrinsics().constructors().string().prototype();
 
                 let object =
@@ -519,14 +419,14 @@ impl JsValue {
                 );
                 Ok(object)
             }
-            Self::Symbol(ref symbol) => {
+            JsVariant::Symbol(symbol) => {
                 let prototype = context.intrinsics().constructors().symbol().prototype();
                 Ok(JsObject::from_proto_and_data(
                     prototype,
                     ObjectData::symbol(symbol.clone()),
                 ))
             }
-            Self::BigInt(ref bigint) => {
+            JsVariant::BigInt(bigint) => {
                 let prototype = context
                     .intrinsics()
                     .constructors()
@@ -537,7 +437,7 @@ impl JsValue {
                     ObjectData::big_int(bigint.clone()),
                 ))
             }
-            Self::Object(jsobject) => Ok(jsobject.clone()),
+            JsVariant::Object(jsobject) => Ok(jsobject.clone()),
         }
     }
 
@@ -545,19 +445,22 @@ impl JsValue {
     ///
     /// See <https://tc39.es/ecma262/#sec-topropertykey>
     pub fn to_property_key(&self, context: &mut Context) -> JsResult<PropertyKey> {
-        Ok(match self {
+        Ok(match self.variant() {
             // Fast path:
-            Self::String(string) => string.clone().into(),
-            Self::Symbol(symbol) => symbol.clone().into(),
-            Self::Integer(integer) => (*integer).into(),
+            JsVariant::String(string) => string.clone().into(),
+            JsVariant::Symbol(symbol) => symbol.clone().into(),
+            JsVariant::Integer32(integer) => integer.into(),
             // Slow path:
-            Self::Object(_) => match self.to_primitive(context, PreferredType::String)? {
-                Self::String(ref string) => string.clone().into(),
-                Self::Symbol(ref symbol) => symbol.clone().into(),
-                Self::Integer(integer) => integer.into(),
-                primitive => primitive.to_string(context)?.into(),
-            },
-            primitive => primitive.to_string(context)?.into(),
+            JsVariant::Object(_) => {
+                let primitive = self.to_primitive(context, PreferredType::String)?;
+                match primitive.variant() {
+                JsVariant::String(string) => string.clone().into(),
+                JsVariant::Symbol(symbol) => symbol.clone().into(),
+                JsVariant::Integer32(integer) => integer.into(),
+                _ => primitive.to_string(context)?.into(),
+            }
+        },
+            _ => self.to_string(context)?.into(),
         })
     }
 
@@ -579,7 +482,7 @@ impl JsValue {
     /// See: <https://tc39.es/ecma262/#sec-touint32>
     pub fn to_u32(&self, context: &mut Context) -> JsResult<u32> {
         // This is the fast path, if the value is Integer we can just return it.
-        if let JsValue::Integer(number) = *self {
+        if let Some(number) = self.as_integer32() {
             return Ok(number as u32);
         }
         let number = self.to_number(context)?;
@@ -592,7 +495,7 @@ impl JsValue {
     /// See: <https://tc39.es/ecma262/#sec-toint32>
     pub fn to_i32(&self, context: &mut Context) -> JsResult<i32> {
         // This is the fast path, if the value is Integer we can just return it.
-        if let JsValue::Integer(number) = *self {
+        if let Some(number) = self.as_integer32() {
             return Ok(number);
         }
         let number = self.to_number(context)?;
@@ -873,16 +776,16 @@ impl JsValue {
     ///
     /// See: <https://tc39.es/ecma262/#sec-tonumber>
     pub fn to_number(&self, context: &mut Context) -> JsResult<f64> {
-        match *self {
-            Self::Null => Ok(0.0),
-            Self::Undefined => Ok(f64::NAN),
-            Self::Boolean(b) => Ok(if b { 1.0 } else { 0.0 }),
-            Self::String(ref string) => Ok(string.string_to_number()),
-            Self::Rational(number) => Ok(number),
-            Self::Integer(integer) => Ok(f64::from(integer)),
-            Self::Symbol(_) => context.throw_type_error("argument must not be a symbol"),
-            Self::BigInt(_) => context.throw_type_error("argument must not be a bigint"),
-            Self::Object(_) => {
+        match self.variant() {
+            JsVariant::Null => Ok(0.0),
+            JsVariant::Undefined => Ok(f64::NAN),
+            JsVariant::Boolean(b) => Ok(if b { 1.0 } else { 0.0 }),
+            JsVariant::String(string) => Ok(string.string_to_number()),
+            JsVariant::Float64(number) => Ok(number),
+            JsVariant::Integer32(integer) => Ok(f64::from(integer)),
+            JsVariant::Symbol(_) => context.throw_type_error("argument must not be a symbol"),
+            JsVariant::BigInt(_) => context.throw_type_error("argument must not be a bigint"),
+            JsVariant::Object(_) => {
                 let primitive = self.to_primitive(context, PreferredType::Number)?;
                 primitive.to_number(context)
             }
@@ -942,15 +845,15 @@ impl JsValue {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typeof-operator
     pub fn type_of(&self) -> JsString {
-        match *self {
-            Self::Rational(_) | Self::Integer(_) => "number",
-            Self::String(_) => "string",
-            Self::Boolean(_) => "boolean",
-            Self::Symbol(_) => "symbol",
-            Self::Null => "object",
-            Self::Undefined => "undefined",
-            Self::BigInt(_) => "bigint",
-            Self::Object(ref object) => {
+        match self.variant() {
+            JsVariant::Float64(_) | JsVariant::Integer32(_) => "number",
+            JsVariant::String(_) => "string",
+            JsVariant::Boolean(_) => "boolean",
+            JsVariant::Symbol(_) => "symbol",
+            JsVariant::Null => "object",
+            JsVariant::Undefined => "undefined",
+            JsVariant::BigInt(_) => "bigint",
+            JsVariant::Object(object) => {
                 if object.is_callable() {
                     "function"
                 } else {
@@ -986,7 +889,7 @@ impl JsValue {
 
 impl Default for JsValue {
     fn default() -> Self {
-        Self::Undefined
+        Self::undefined()
     }
 }
 
diff --git a/boa_engine/src/value/operations.rs b/boa_engine/src/value/operations.rs
index 4e45f6790e..238e25397c 100644
--- a/boa_engine/src/value/operations.rs
+++ b/boa_engine/src/value/operations.rs
@@ -1,5 +1,5 @@
 use super::{
-    Context, FromStr, JsBigInt, JsResult, JsString, JsValue, Numeric, PreferredType,
+    Context, FromStr, JsBigInt, JsResult, JsString, JsValue, JsVariant, Numeric, PreferredType,
     WellKnownSymbols,
 };
 use crate::builtins::number::{f64_to_int32, f64_to_uint32, Number};
@@ -7,60 +7,63 @@ use crate::builtins::number::{f64_to_int32, f64_to_uint32, Number};
 impl JsValue {
     #[inline]
     pub fn add(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
             // Numeric add
-            (Self::Integer(x), Self::Integer(y)) => x
-                .checked_add(*y)
-                .map_or_else(|| Self::new(f64::from(*x) + f64::from(*y)), Self::new),
-            (Self::Rational(x), Self::Rational(y)) => Self::new(x + y),
-            (Self::Integer(x), Self::Rational(y)) => Self::new(f64::from(*x) + y),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(x + f64::from(*y)),
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => Self::new(JsBigInt::add(x, y)),
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => x
+                .checked_add(y)
+                .map_or_else(|| Self::new(f64::from(x) + f64::from(y)), Self::new),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Self::new(x + y),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(f64::from(x) + y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(x + f64::from(y)),
+            (JsVariant::BigInt(x), JsVariant::BigInt(y)) => Self::new(JsBigInt::add(&*x, &*y)),
 
             // String concat
-            (Self::String(ref x), Self::String(ref y)) => Self::from(JsString::concat(x, y)),
-            (Self::String(ref x), y) => Self::from(JsString::concat(x, y.to_string(context)?)),
-            (x, Self::String(ref y)) => Self::from(JsString::concat(x.to_string(context)?, y)),
+            (JsVariant::String(x), JsVariant::String(y)) => Self::from(JsString::concat(&*x, &*y)),
+            (JsVariant::String(x), _) => {
+                Self::new(JsString::concat(&*x, other.to_string(context)?))
+            }
+            (_, JsVariant::String(y)) => Self::new(JsString::concat(self.to_string(context)?, &*y)),
 
             // Slow path:
-            (_, _) => match (
-                self.to_primitive(context, PreferredType::Default)?,
-                other.to_primitive(context, PreferredType::Default)?,
-            ) {
-                (Self::String(ref x), ref y) => {
-                    Self::from(JsString::concat(x, y.to_string(context)?))
-                }
-                (ref x, Self::String(ref y)) => {
-                    Self::from(JsString::concat(x.to_string(context)?, y))
-                }
-                (x, y) => match (x.to_numeric(context)?, y.to_numeric(context)?) {
-                    (Numeric::Number(x), Numeric::Number(y)) => Self::new(x + y),
-                    (Numeric::BigInt(ref x), Numeric::BigInt(ref y)) => {
-                        Self::new(JsBigInt::add(x, y))
+            (_, _) => {
+                let x = self.to_primitive(context, PreferredType::Default)?;
+                let y = other.to_primitive(context, PreferredType::Default)?;
+                match (x.variant(), y.variant()) {
+                    (JsVariant::String(x), _) => {
+                        Self::from(JsString::concat(&*x, y.to_string(context)?))
                     }
-                    (_, _) => {
-                        return context.throw_type_error(
-                            "cannot mix BigInt and other types, use explicit conversions",
-                        )
+                    (_, JsVariant::String(y)) => {
+                        Self::from(JsString::concat(x.to_string(context)?, &*y))
                     }
-                },
-            },
+                    (_, _) => match (x.to_numeric(context)?, y.to_numeric(context)?) {
+                        (Numeric::Number(x), Numeric::Number(y)) => Self::new(x + y),
+                        (Numeric::BigInt(ref x), Numeric::BigInt(ref y)) => {
+                            Self::new(JsBigInt::add(x, y))
+                        }
+                        (_, _) => {
+                            return context.throw_type_error(
+                                "cannot mix BigInt and other types, use explicit conversions",
+                            )
+                        }
+                    },
+                }
+            }
         })
     }
 
     #[inline]
     pub fn sub(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => x
-                .checked_sub(*y)
-                .map_or_else(|| Self::new(f64::from(*x) - f64::from(*y)), Self::new),
-            (Self::Rational(x), Self::Rational(y)) => Self::new(x - y),
-            (Self::Integer(x), Self::Rational(y)) => Self::new(f64::from(*x) - y),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(x - f64::from(*y)),
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => x
+                .checked_sub(y)
+                .map_or_else(|| Self::new(f64::from(x) - f64::from(y)), Self::new),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Self::new(x - y),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(f64::from(x) - y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(x - f64::from(y)),
 
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => Self::new(JsBigInt::sub(x, y)),
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => Self::new(JsBigInt::sub(x, y)),
 
             // Slow path:
             (_, _) => match (self.to_numeric(context)?, other.to_numeric(context)?) {
@@ -77,16 +80,16 @@ impl JsValue {
 
     #[inline]
     pub fn mul(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => x
-                .checked_mul(*y)
-                .map_or_else(|| Self::new(f64::from(*x) * f64::from(*y)), Self::new),
-            (Self::Rational(x), Self::Rational(y)) => Self::new(x * y),
-            (Self::Integer(x), Self::Rational(y)) => Self::new(f64::from(*x) * y),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(x * f64::from(*y)),
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => x
+                .checked_mul(y)
+                .map_or_else(|| Self::new(f64::from(x) * f64::from(y)), Self::new),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Self::new(x * y),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(f64::from(x) * y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(x * f64::from(y)),
 
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => Self::new(JsBigInt::mul(x, y)),
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => Self::new(JsBigInt::mul(x, y)),
 
             // Slow path:
             (_, _) => match (self.to_numeric(context)?, other.to_numeric(context)?) {
@@ -103,17 +106,17 @@ impl JsValue {
 
     #[inline]
     pub fn div(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => x
-                .checked_div(*y)
-                .filter(|div| *y * div == *x)
-                .map_or_else(|| Self::new(f64::from(*x) / f64::from(*y)), Self::new),
-            (Self::Rational(x), Self::Rational(y)) => Self::new(x / y),
-            (Self::Integer(x), Self::Rational(y)) => Self::new(f64::from(*x) / y),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(x / f64::from(*y)),
-
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => {
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => x
+                .checked_div(y)
+                .filter(|div| y * div == x)
+                .map_or_else(|| Self::new(f64::from(x) / f64::from(y)), Self::new),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Self::new(x / y),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(f64::from(x) / y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(x / f64::from(y)),
+
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => {
                 if y.is_zero() {
                     return context.throw_range_error("BigInt division by zero");
                 }
@@ -140,33 +143,32 @@ impl JsValue {
 
     #[inline]
     pub fn rem(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => {
-                if *y == 0 {
-                    Self::nan()
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => {
+                if y == 0 {
+                    Self::from(f64::NAN)
                 } else {
-                    match x % *y {
-                        rem if rem == 0 && *x < 0 => Self::new(-0.0),
+                    match x % y {
+                        rem if rem == 0 && x < 0 => Self::new(-0.0),
                         rem => Self::new(rem),
                     }
                 }
             }
-            (Self::Rational(x), Self::Rational(y)) => Self::new((x % y).copysign(*x)),
-            (Self::Integer(x), Self::Rational(y)) => {
-                let x = f64::from(*x);
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Self::new((x % y).copysign(x)),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => {
+                let x = f64::from(x);
                 Self::new((x % y).copysign(x))
             }
-
-            (Self::Rational(x), Self::Integer(y)) => Self::new((x % f64::from(*y)).copysign(*x)),
-
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => {
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => {
+                Self::new((x % f64::from(y)).copysign(x))
+            }
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => {
                 if y.is_zero() {
                     return context.throw_range_error("BigInt division by zero");
                 }
                 Self::new(JsBigInt::rem(x, y))
             }
-
             // Slow path:
             (_, _) => match (self.to_numeric(context)?, other.to_numeric(context)?) {
                 (Numeric::Number(a), Numeric::Number(b)) => Self::new(a % b),
@@ -187,17 +189,19 @@ impl JsValue {
 
     #[inline]
     pub fn pow(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => u32::try_from(*y)
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => u32::try_from(y)
                 .ok()
                 .and_then(|y| x.checked_pow(y))
-                .map_or_else(|| Self::new(f64::from(*x).powi(*y)), Self::new),
-            (Self::Rational(x), Self::Rational(y)) => Self::new(x.powf(*y)),
-            (Self::Integer(x), Self::Rational(y)) => Self::new(f64::from(*x).powf(*y)),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(x.powi(*y)),
+                .map_or_else(|| Self::new(f64::from(x).powi(y)), Self::new),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Self::new(x.powf(y)),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(f64::from(x).powf(y)),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(x.powi(y)),
 
-            (Self::BigInt(ref a), Self::BigInt(ref b)) => Self::new(JsBigInt::pow(a, b, context)?),
+            (JsVariant::BigInt(ref a), JsVariant::BigInt(ref b)) => {
+                Self::new(JsBigInt::pow(a, b, context)?)
+            }
 
             // Slow path:
             (_, _) => match (self.to_numeric(context)?, other.to_numeric(context)?) {
@@ -216,16 +220,18 @@ impl JsValue {
 
     #[inline]
     pub fn bitand(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => Self::new(x & y),
-            (Self::Rational(x), Self::Rational(y)) => {
-                Self::new(f64_to_int32(*x) & f64_to_int32(*y))
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => Self::new(x & y),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => {
+                Self::new(f64_to_int32(x) & f64_to_int32(y))
             }
-            (Self::Integer(x), Self::Rational(y)) => Self::new(x & f64_to_int32(*y)),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(f64_to_int32(*x) & y),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(x & f64_to_int32(y)),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(f64_to_int32(x) & y),
 
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => Self::new(JsBigInt::bitand(x, y)),
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => {
+                Self::new(JsBigInt::bitand(x, y))
+            }
 
             // Slow path:
             (_, _) => match (self.to_numeric(context)?, other.to_numeric(context)?) {
@@ -246,16 +252,18 @@ impl JsValue {
 
     #[inline]
     pub fn bitor(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => Self::new(x | y),
-            (Self::Rational(x), Self::Rational(y)) => {
-                Self::new(f64_to_int32(*x) | f64_to_int32(*y))
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => Self::new(x | y),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => {
+                Self::new(f64_to_int32(x) | f64_to_int32(y))
             }
-            (Self::Integer(x), Self::Rational(y)) => Self::new(x | f64_to_int32(*y)),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(f64_to_int32(*x) | y),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(x | f64_to_int32(y)),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(f64_to_int32(x) | y),
 
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => Self::new(JsBigInt::bitor(x, y)),
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => {
+                Self::new(JsBigInt::bitor(x, y))
+            }
 
             // Slow path:
             (_, _) => match (self.to_numeric(context)?, other.to_numeric(context)?) {
@@ -276,16 +284,18 @@ impl JsValue {
 
     #[inline]
     pub fn bitxor(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => Self::new(x ^ y),
-            (Self::Rational(x), Self::Rational(y)) => {
-                Self::new(f64_to_int32(*x) ^ f64_to_int32(*y))
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => Self::new(x ^ y),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => {
+                Self::new(f64_to_int32(x) ^ f64_to_int32(y))
             }
-            (Self::Integer(x), Self::Rational(y)) => Self::new(x ^ f64_to_int32(*y)),
-            (Self::Rational(x), Self::Integer(y)) => Self::new(f64_to_int32(*x) ^ y),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Self::new(x ^ f64_to_int32(y)),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Self::new(f64_to_int32(x) ^ y),
 
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => Self::new(JsBigInt::bitxor(x, y)),
+            (JsVariant::BigInt(ref x), JsVariant::BigInt(ref y)) => {
+                Self::new(JsBigInt::bitxor(x, y))
+            }
 
             // Slow path:
             (_, _) => match (self.to_numeric(context)?, other.to_numeric(context)?) {
@@ -306,18 +316,22 @@ impl JsValue {
 
     #[inline]
     pub fn shl(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => Self::new(x.wrapping_shl(*y as u32)),
-            (Self::Rational(x), Self::Rational(y)) => {
-                Self::new(f64_to_int32(*x).wrapping_shl(f64_to_uint32(*y)))
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => {
+                Self::new(x.wrapping_shl(y as u32))
             }
-            (Self::Integer(x), Self::Rational(y)) => Self::new(x.wrapping_shl(f64_to_uint32(*y))),
-            (Self::Rational(x), Self::Integer(y)) => {
-                Self::new(f64_to_int32(*x).wrapping_shl(*y as u32))
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => {
+                Self::new(f64_to_int32(x).wrapping_shl(f64_to_uint32(y)))
+            }
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => {
+                Self::new(x.wrapping_shl(f64_to_uint32(y)))
+            }
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => {
+                Self::new(f64_to_int32(x).wrapping_shl(y as u32))
             }
 
-            (Self::BigInt(ref a), Self::BigInt(ref b)) => {
+            (JsVariant::BigInt(ref a), JsVariant::BigInt(ref b)) => {
                 Self::new(JsBigInt::shift_left(a, b, context)?)
             }
 
@@ -340,18 +354,22 @@ impl JsValue {
 
     #[inline]
     pub fn shr(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => Self::new(x.wrapping_shr(*y as u32)),
-            (Self::Rational(x), Self::Rational(y)) => {
-                Self::new(f64_to_int32(*x).wrapping_shr(f64_to_uint32(*y)))
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => {
+                Self::new(x.wrapping_shr(y as u32))
+            }
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => {
+                Self::new(f64_to_int32(x).wrapping_shr(f64_to_uint32(y)))
             }
-            (Self::Integer(x), Self::Rational(y)) => Self::new(x.wrapping_shr(f64_to_uint32(*y))),
-            (Self::Rational(x), Self::Integer(y)) => {
-                Self::new(f64_to_int32(*x).wrapping_shr(*y as u32))
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => {
+                Self::new(x.wrapping_shr(f64_to_uint32(y)))
+            }
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => {
+                Self::new(f64_to_int32(x).wrapping_shr(y as u32))
             }
 
-            (Self::BigInt(ref a), Self::BigInt(ref b)) => {
+            (JsVariant::BigInt(ref a), JsVariant::BigInt(ref b)) => {
                 Self::new(JsBigInt::shift_right(a, b, context)?)
             }
 
@@ -374,17 +392,19 @@ impl JsValue {
 
     #[inline]
     pub fn ushr(&self, other: &Self, context: &mut Context) -> JsResult<Self> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path:
-            (Self::Integer(x), Self::Integer(y)) => Self::new((*x as u32).wrapping_shr(*y as u32)),
-            (Self::Rational(x), Self::Rational(y)) => {
-                Self::new(f64_to_uint32(*x).wrapping_shr(f64_to_uint32(*y)))
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => {
+                Self::new((x as u32).wrapping_shr(y as u32))
+            }
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => {
+                Self::new(f64_to_uint32(x).wrapping_shr(f64_to_uint32(y)))
             }
-            (Self::Integer(x), Self::Rational(y)) => {
-                Self::new((*x as u32).wrapping_shr(f64_to_uint32(*y)))
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => {
+                Self::new((x as u32).wrapping_shr(f64_to_uint32(y)))
             }
-            (Self::Rational(x), Self::Integer(y)) => {
-                Self::new(f64_to_uint32(*x).wrapping_shr(*y as u32))
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => {
+                Self::new(f64_to_uint32(x).wrapping_shr(y as u32))
             }
 
             // Slow path:
@@ -443,22 +463,22 @@ impl JsValue {
 
     #[inline]
     pub fn neg(&self, context: &mut Context) -> JsResult<Self> {
-        Ok(match *self {
-            Self::Symbol(_) | Self::Undefined => Self::new(f64::NAN),
-            Self::Object(_) => Self::new(match self.to_numeric_number(context) {
+        Ok(match self.variant() {
+            JsVariant::Symbol(_) | JsVariant::Undefined => Self::new(f64::NAN),
+            JsVariant::Object(_) => Self::new(match self.to_numeric_number(context) {
                 Ok(num) => -num,
                 Err(_) => f64::NAN,
             }),
-            Self::String(ref str) => Self::new(match f64::from_str(str) {
+            JsVariant::String(ref str) => Self::new(match f64::from_str(str) {
                 Ok(num) => -num,
                 Err(_) => f64::NAN,
             }),
-            Self::Rational(num) => Self::new(-num),
-            Self::Integer(num) if num == 0 => Self::new(-f64::from(0)),
-            Self::Integer(num) => Self::new(-num),
-            Self::Boolean(true) => Self::new(1),
-            Self::Boolean(false) | Self::Null => Self::new(0),
-            Self::BigInt(ref x) => Self::new(JsBigInt::neg(x)),
+            JsVariant::Float64(num) => Self::new(-num),
+            JsVariant::Integer32(num) if num == 0 => Self::new(-f64::from(0)),
+            JsVariant::Integer32(num) => Self::new(-num),
+            JsVariant::Boolean(true) => Self::new(1),
+            JsVariant::Boolean(false) | JsVariant::Null => Self::new(0),
+            JsVariant::BigInt(ref x) => Self::new(JsBigInt::neg(x)),
         })
     }
 
@@ -490,13 +510,13 @@ impl JsValue {
         left_first: bool,
         context: &mut Context,
     ) -> JsResult<AbstractRelation> {
-        Ok(match (self, other) {
+        Ok(match (self.variant(), other.variant()) {
             // Fast path (for some common operations):
-            (Self::Integer(x), Self::Integer(y)) => (x < y).into(),
-            (Self::Integer(x), Self::Rational(y)) => Number::less_than(f64::from(*x), *y),
-            (Self::Rational(x), Self::Integer(y)) => Number::less_than(*x, f64::from(*y)),
-            (Self::Rational(x), Self::Rational(y)) => Number::less_than(*x, *y),
-            (Self::BigInt(ref x), Self::BigInt(ref y)) => (x < y).into(),
+            (JsVariant::Integer32(x), JsVariant::Integer32(y)) => (x < y).into(),
+            (JsVariant::Integer32(x), JsVariant::Float64(y)) => Number::less_than(f64::from(x), y),
+            (JsVariant::Float64(x), JsVariant::Integer32(y)) => Number::less_than(x, f64::from(y)),
+            (JsVariant::Float64(x), JsVariant::Float64(y)) => Number::less_than(x, y),
+            (JsVariant::BigInt(x), JsVariant::BigInt(y)) => (x < y).into(),
 
             // Slow path:
             (_, _) => {
@@ -511,8 +531,8 @@ impl JsValue {
                     (px, py)
                 };
 
-                match (px, py) {
-                    (Self::String(ref x), Self::String(ref y)) => {
+                match (px.variant(), py.variant()) {
+                    (JsVariant::String(x), JsVariant::String(y)) => {
                         if x.starts_with(y.as_str()) {
                             return Ok(AbstractRelation::False);
                         }
@@ -526,21 +546,21 @@ impl JsValue {
                         }
                         unreachable!()
                     }
-                    (Self::BigInt(ref x), Self::String(ref y)) => {
+                    (JsVariant::BigInt(x), JsVariant::String(ref y)) => {
                         if let Some(y) = JsBigInt::from_string(y) {
                             (*x < y).into()
                         } else {
                             AbstractRelation::Undefined
                         }
                     }
-                    (Self::String(ref x), Self::BigInt(ref y)) => {
+                    (JsVariant::String(ref x), JsVariant::BigInt(y)) => {
                         if let Some(x) = JsBigInt::from_string(x) {
                             (x < *y).into()
                         } else {
                             AbstractRelation::Undefined
                         }
                     }
-                    (px, py) => match (px.to_numeric(context)?, py.to_numeric(context)?) {
+                    (_, _) => match (px.to_numeric(context)?, py.to_numeric(context)?) {
                         (Numeric::Number(x), Numeric::Number(y)) => Number::less_than(x, y),
                         (Numeric::BigInt(ref x), Numeric::BigInt(ref y)) => (x < y).into(),
                         (Numeric::BigInt(ref x), Numeric::Number(y)) => {
diff --git a/boa_engine/src/value/serde_json.rs b/boa_engine/src/value/serde_json.rs
index 645e7ae361..79f303453c 100644
--- a/boa_engine/src/value/serde_json.rs
+++ b/boa_engine/src/value/serde_json.rs
@@ -1,6 +1,6 @@
 //! This module implements the conversions from and into [`serde_json::Value`].
 
-use super::JsValue;
+use super::{JsValue, JsVariant};
 use crate::{
     builtins::Array,
     property::{PropertyDescriptor, PropertyKey},
@@ -41,13 +41,13 @@ impl JsValue {
         const MIN_INT: i64 = i32::MIN as i64;
 
         match json {
-            Value::Null => Ok(Self::Null),
-            Value::Bool(b) => Ok(Self::Boolean(*b)),
+            Value::Null => Ok(Self::null()),
+            Value::Bool(b) => Ok(Self::from(*b)),
             Value::Number(num) => num
                 .as_i64()
                 .filter(|n| (MIN_INT..=MAX_INT).contains(n))
-                .map(|i| Self::Integer(i as i32))
-                .or_else(|| num.as_f64().map(Self::Rational))
+                .map(|i| Self::from(i as i32))
+                .or_else(|| num.as_f64().map(Self::from))
                 .ok_or_else(|| {
                     context.construct_type_error(format!(
                         "could not convert JSON number {num} to JsValue"
@@ -104,15 +104,15 @@ impl JsValue {
     /// # assert_eq!(json, back_to_json);
     /// ```
     pub fn to_json(&self, context: &mut Context) -> JsResult<Value> {
-        match self {
-            Self::Null => Ok(Value::Null),
-            Self::Undefined => todo!("undefined to JSON"),
-            &Self::Boolean(b) => Ok(b.into()),
-            Self::String(string) => Ok(string.as_str().into()),
-            &Self::Rational(rat) => Ok(rat.into()),
-            &Self::Integer(int) => Ok(int.into()),
-            Self::BigInt(_bigint) => context.throw_type_error("cannot convert bigint to JSON"),
-            Self::Object(obj) => {
+        match self.variant() {
+            JsVariant::Null => Ok(Value::Null),
+            JsVariant::Undefined => todo!("undefined to JSON"),
+            JsVariant::Boolean(b) => Ok(b.into()),
+            JsVariant::String(string) => Ok(string.as_str().into()),
+            JsVariant::Float64(rat) => Ok(rat.into()),
+            JsVariant::Integer32(int) => Ok(int.into()),
+            JsVariant::BigInt(_bigint) => context.throw_type_error("cannot convert bigint to JSON"),
+            JsVariant::Object(obj) => {
                 if obj.is_array() {
                     let len = obj.length_of_array_like(context)?;
                     let mut arr = Vec::with_capacity(len as usize);
@@ -120,9 +120,12 @@ impl JsValue {
                     let obj = obj.borrow();
 
                     for k in 0..len as u32 {
-                        let val = obj.properties().get(&k.into()).map_or(Self::Null, |desc| {
-                            desc.value().cloned().unwrap_or(Self::Null)
-                        });
+                        let val = obj
+                            .properties()
+                            .get(&k.into())
+                            .map_or(Self::null(), |desc| {
+                                desc.value().cloned().unwrap_or(Self::null())
+                            });
                         arr.push(val.to_json(context)?);
                     }
 
@@ -149,7 +152,7 @@ impl JsValue {
                     Ok(Value::Object(map))
                 }
             }
-            Self::Symbol(_sym) => context.throw_type_error("cannot convert Symbol to JSON"),
+            JsVariant::Symbol(_sym) => context.throw_type_error("cannot convert Symbol to JSON"),
         }
     }
 }
diff --git a/boa_engine/src/value/sys/default.rs b/boa_engine/src/value/sys/default.rs
new file mode 100644
index 0000000000..3dd72466b8
--- /dev/null
+++ b/boa_engine/src/value/sys/default.rs
@@ -0,0 +1,290 @@
+use boa_gc::{custom_trace, Finalize, Trace};
+
+use super::JsVariant;
+
+use crate::{object::JsObject, JsBigInt, JsString, JsSymbol};
+
+#[derive(Finalize, Debug, Clone)]
+enum Value {
+    Null,
+    Undefined,
+    Boolean(bool),
+    Integer32(i32),
+    Float64(f64),
+    String(JsString),
+    BigInt(JsBigInt),
+    Symbol(JsSymbol),
+    Object(JsObject),
+}
+
+#[allow(unsafe_op_in_unsafe_fn)]
+unsafe impl Trace for Value {
+    custom_trace! {this, {
+        if let Self::Object(o) = this {
+            mark(o);
+        }
+    }}
+}
+
+/// A Javascript value
+///
+/// Check the [`value`][`super::super`] module for more information.
+#[derive(Trace, Finalize, Debug, Clone)]
+pub struct JsValue(Value);
+
+impl JsValue {
+    /// `null` - A null value, for when a value doesn't exist.
+    #[inline]
+    pub const fn null() -> Self {
+        Self(Value::Null)
+    }
+
+    /// `undefined` - An undefined value, for when a field or index doesn't exist
+    #[inline]
+    pub const fn undefined() -> Self {
+        Self(Value::Undefined)
+    }
+
+    /// `boolean` - A `true` / `false` value.
+    #[inline]
+    pub fn boolean(boolean: bool) -> Self {
+        Self(Value::Boolean(boolean))
+    }
+
+    /// `integer32` - A 32-bit integer value, such as `42`.
+    #[inline]
+    pub fn integer32(integer: i32) -> Self {
+        Self(Value::Integer32(integer))
+    }
+
+    /// `float64` - A 64-bit floating point number value, such as `3.1415`
+    #[inline]
+    pub fn float64(float64: f64) -> Self {
+        Self(Value::Float64(float64))
+    }
+
+    /// `String` - A [`JsString`] value, such as `"Hello, world"`.
+    #[inline]
+    pub fn string(string: JsString) -> Self {
+        Self(Value::String(string))
+    }
+
+    /// `BigInt` - A [`JsBigInt`] value, an arbitrarily large signed integer.
+    #[inline]
+    pub fn bigint(bigint: JsBigInt) -> Self {
+        Self(Value::BigInt(bigint))
+    }
+
+    /// `Symbol` - A [`JsSymbol`] value.
+    #[inline]
+    pub fn symbol(symbol: JsSymbol) -> Self {
+        Self(Value::Symbol(symbol))
+    }
+
+    /// `Object` - A [`JsObject`], such as `Math`, represented by a binary tree of string keys to Javascript values.
+    #[inline]
+    pub fn object(object: JsObject) -> Self {
+        Self(Value::Object(object))
+    }
+
+    /// Returns the internal [`bool`] if the value is a boolean, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_boolean(&self) -> Option<bool> {
+        match self.0 {
+            Value::Boolean(boolean) => Some(boolean),
+            _ => None,
+        }
+    }
+
+    /// Returns the internal [`i32`] if the value is a 32-bit signed integer number, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_integer32(&self) -> Option<i32> {
+        match self.0 {
+            Value::Integer32(integer) => Some(integer),
+            _ => None,
+        }
+    }
+
+    /// Returns the internal [`f64`] if the value is a 64-bit floating-point number, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_float64(&self) -> Option<f64> {
+        match self.0 {
+            Value::Float64(rational) => Some(rational),
+            _ => None,
+        }
+    }
+
+    /// Returns a reference to the internal [`JsString`] if the value is a string, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_string(&self) -> Option<Ref<'_, JsString>> {
+        match self.0 {
+            Value::String(ref inner) => Some(Ref { inner }),
+            _ => None,
+        }
+    }
+
+    /// Returns a reference to the internal [`JsBigInt`] if the value is a big int, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_bigint(&self) -> Option<Ref<'_, JsBigInt>> {
+        match self.0 {
+            Value::BigInt(ref inner) => Some(Ref { inner }),
+            _ => None,
+        }
+    }
+
+    /// Returns a reference to the internal [`JsSymbol`] if the value is a symbol, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_symbol(&self) -> Option<Ref<'_, JsSymbol>> {
+        match self.0 {
+            Value::Symbol(ref inner) => Some(Ref { inner }),
+            _ => None,
+        }
+    }
+
+    /// Returns a reference to the internal [`JsObject`] if the value is an object, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_object(&self) -> Option<Ref<'_, JsObject>> {
+        match self.0 {
+            Value::Object(ref inner) => Some(Ref { inner }),
+            _ => None,
+        }
+    }
+
+    /// Returns true if the value is null.
+    #[inline]
+    pub fn is_null(&self) -> bool {
+        matches!(self.0, Value::Null)
+    }
+
+    /// Returns true if the value is undefined.
+    #[inline]
+    pub fn is_undefined(&self) -> bool {
+        matches!(self.0, Value::Undefined)
+    }
+
+    /// Returns true if the value is a boolean.
+    #[inline]
+    pub fn is_boolean(&self) -> bool {
+        matches!(self.0, Value::Boolean(_))
+    }
+
+    /// Returns true if the value is a 32-bit signed integer number.
+    #[inline]
+    pub fn is_integer32(&self) -> bool {
+        matches!(self.0, Value::Integer32(_))
+    }
+
+    /// Returns true if the value is a 64-bit floating-point number.
+    #[inline]
+    pub fn is_float64(&self) -> bool {
+        matches!(self.0, Value::Float64(_))
+    }
+
+    /// Returns true if the value is a 64-bit floating-point `NaN` number.
+    #[inline]
+    pub fn is_nan(&self) -> bool {
+        matches!(self.0, Value::Float64(r) if r.is_nan())
+    }
+
+    /// Returns true if the value is a string.
+    #[inline]
+    pub fn is_string(&self) -> bool {
+        matches!(self.0, Value::String(_))
+    }
+
+    /// Returns true if the value is a bigint.
+    #[inline]
+    pub fn is_bigint(&self) -> bool {
+        matches!(self.0, Value::BigInt(_))
+    }
+
+    /// Returns true if the value is a symbol.
+    #[inline]
+    pub fn is_symbol(&self) -> bool {
+        matches!(self.0, Value::Symbol(_))
+    }
+
+    /// Returns true if the value is an object
+    #[inline]
+    pub fn is_object(&self) -> bool {
+        matches!(self.0, Value::Object(_))
+    }
+
+    /// Returns a [`JsVariant`] enum representing the current variant of the value.
+    ///
+    /// # Note
+    ///
+    /// More exotic implementations of [`JsValue`] cannot use direct references to
+    /// heap based types, so [`JsVariant`] instead returns [`Ref`]s on those cases.
+    pub fn variant(&self) -> JsVariant<'_> {
+        match self.0 {
+            Value::Null => JsVariant::Null,
+            Value::Undefined => JsVariant::Undefined,
+            Value::Integer32(i) => JsVariant::Integer32(i),
+            Value::Float64(d) => JsVariant::Float64(d),
+            Value::Boolean(b) => JsVariant::Boolean(b),
+            Value::Object(ref inner) => JsVariant::Object(Ref { inner }),
+            Value::String(ref inner) => JsVariant::String(Ref { inner }),
+            Value::Symbol(ref inner) => JsVariant::Symbol(Ref { inner }),
+            Value::BigInt(ref inner) => JsVariant::BigInt(Ref { inner }),
+        }
+    }
+}
+
+/// Represents a reference to a boxed pointer type inside a [`JsValue`]
+///
+/// This is exclusively used to return references to [`JsString`], [`JsObject`],
+/// [`JsSymbol`] and [`JsBigInt`], since some [`JsValue`] implementations makes
+/// returning proper references difficult.
+/// It is mainly returned by the [`JsValue::variant`] method and the
+/// `as_` methods for checked casts to pointer types.
+///
+/// [`Ref`] implements [`Deref`][`std::ops::Deref`], which facilitates conversion
+/// to a proper [`reference`] by using the `ref` keyword or the
+/// [`Option::as_deref`][`std::option::Option::as_deref`] method.
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Ref<'a, T> {
+    inner: &'a T,
+}
+
+// Lift `Ref` over `AsRef`, since implementing `AsRef<T>` would override the
+// `as_ref` implementations of `T`.
+impl<U, T> AsRef<U> for Ref<'_, T>
+where
+    T: AsRef<U>,
+{
+    #[inline]
+    fn as_ref(&self) -> &U {
+        <T as AsRef<U>>::as_ref(self.inner)
+    }
+}
+
+impl<T> std::ops::Deref for Ref<'_, T> {
+    type Target = T;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        self.inner
+    }
+}
+
+impl<T: PartialEq> PartialEq<T> for Ref<'_, T> {
+    #[inline]
+    fn eq(&self, other: &T) -> bool {
+        self.inner == other
+    }
+}
+
+impl<T> std::borrow::Borrow<T> for Ref<'_, T> {
+    #[inline]
+    fn borrow(&self) -> &T {
+        self.inner
+    }
+}
diff --git a/boa_engine/src/value/sys/mod.rs b/boa_engine/src/value/sys/mod.rs
new file mode 100644
index 0000000000..a657724012
--- /dev/null
+++ b/boa_engine/src/value/sys/mod.rs
@@ -0,0 +1,99 @@
+//! This module contains various implementations of the [`JsValue`] type, and
+//! type redefinitions to select the requested [`JsValue`] implementation at
+//! compile time, using features.
+
+use crate::{object::JsObject, JsBigInt, JsString, JsSymbol};
+use std::mem::ManuallyDrop;
+
+// Minimum required definition for a correct `JsValue` implementation:
+
+// pub const fn null() -> Self;
+// pub const fn undefined() -> Self;
+// pub fn boolean(bool) -> Self;
+// pub fn integer(i32) -> Self;
+// pub fn rational(f64) -> Self;
+// pub const fn nan() -> Self;
+// pub fn string(JsString) -> Self;
+// pub fn bigint(JsBigInt) -> Self;
+// pub fn symbol(JsSymbol) -> Self;
+// pub fn object(JsObject) -> Self;
+
+// pub fn as_boolean(&self) -> Option<bool>;
+// pub fn as_integer(&self) -> Option<i32>;
+// pub fn as_rational(&self) -> Option<f64>;
+// pub fn as_string(&self) -> Option<Ref<'_, JsString>>;
+// pub fn as_bigint(&self) -> Option<Ref<'_, JsBigInt>>;
+// pub fn as_symbol(&self) -> Option<Ref<'_, JsSymbol>>;
+// pub fn as_object(&self) -> Option<Ref<'_, JsObject>>;
+
+// pub fn is_null(&self) -> bool;
+// pub fn is_undefined(&self) -> bool;
+// pub fn is_boolean(&self) -> bool;
+// pub fn is_integer(&self) -> bool;
+// pub fn is_rational(&self) -> bool;
+// pub fn is_nan(&self) -> bool;
+// pub fn is_string(&self) -> bool;
+// pub fn is_bigint(&self) -> bool;
+// pub fn is_symbol(&self) -> bool;
+// pub fn is_object(&self) -> bool;
+
+// pub fn variant(&self) -> JsVariant<'_>;
+
+// Ref<'a, T> type
+
+cfg_if::cfg_if! {
+    if #[cfg(all(feature = "nan_boxing", not(doc)))] {
+        cfg_if::cfg_if! {
+            if #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] {
+
+                #[path = "nan_boxed.rs"]
+                mod r#impl;
+
+            } else {
+                compile_error!("This platform doesn't support NaN-boxing.");
+            }
+        }
+    } else {
+        #[path = "default.rs"]
+        mod r#impl;
+    }
+}
+
+pub use r#impl::*;
+
+/// Return value of the [`JsValue::variant`] method.
+///
+/// Represents either a primitive value ([`bool`], [`f64`], [`i32`]) or a reference
+/// to a heap allocated value ([`JsString`], [`JsSymbol`]).
+///
+/// References to heap allocated values are represented by [`Ref`], since
+/// more exotic implementations of [`JsValue`] such as nan-boxed ones cannot
+/// effectively return references.
+#[derive(Debug)]
+pub enum JsVariant<'a> {
+    Null,
+    Undefined,
+    Boolean(bool),
+    Integer32(i32),
+    Float64(f64),
+    String(Ref<'a, JsString>),
+    BigInt(Ref<'a, JsBigInt>),
+    Symbol(Ref<'a, JsSymbol>),
+    Object(Ref<'a, JsObject>),
+}
+
+/// This abstracts over every pointer type and the required conversions
+/// for some of the [`JsValue`] implementations.
+///
+/// # Safety
+///
+/// Non-exhaustive list of situations that could cause undefined behaviour:
+/// - Returning an invalid `*mut ()`.
+/// - Returning a `ManuallyDrop<Self>` that doesn't correspond with the provided
+/// `ptr`.
+/// - Dropping `ty` before returning its pointer.
+pub(crate) unsafe trait PointerType {
+    unsafe fn from_void_ptr(ptr: *mut ()) -> ManuallyDrop<Self>;
+
+    unsafe fn into_void_ptr(ty: ManuallyDrop<Self>) -> *mut ();
+}
diff --git a/boa_engine/src/value/sys/nan_boxed.rs b/boa_engine/src/value/sys/nan_boxed.rs
new file mode 100644
index 0000000000..45221a1bf1
--- /dev/null
+++ b/boa_engine/src/value/sys/nan_boxed.rs
@@ -0,0 +1,760 @@
+#![allow(unstable_name_collisions)]
+
+use num_enum::TryFromPrimitive;
+use std::cell::Cell;
+use std::marker::PhantomData;
+use std::mem::ManuallyDrop;
+
+use boa_gc::{Finalize, Trace};
+
+// TODO: Remove if/when https://github.com/rust-lang/rust/issues/95228 gets stabilized
+use sptr::Strict;
+
+use super::JsVariant;
+
+use crate::{object::JsObject, value::PointerType, JsBigInt, JsString, JsSymbol};
+
+// Our `cfg` options must ensure `usize == u64`.
+// Using `usize`s only makes it more convenient to use in this module
+
+const SIGN_BIT: usize = 0x8000_0000_0000_0000;
+const EXPONENT: usize = 0x7FF0_0000_0000_0000;
+// const MANTISA: usize = 0x000F_FFFF_FFFF_FFFF;
+const SIGNAL_BIT: usize = 0x0008_0000_0000_0000;
+const QNAN: usize = EXPONENT | SIGNAL_BIT; // 0x7FF8000000000000
+
+const CANONICALIZED_NAN: usize = QNAN;
+// const PAYLOAD: usize = 0x0000_7FFF_FFFF_FFFF;
+// const TYPE: usize = !PAYLOAD;
+
+const TAG_MASK: usize = 0xFFFF_0000_0000_0000;
+
+const DOUBLE_TYPE: usize = QNAN;
+const INTEGER_TYPE: usize = QNAN | (0b001 << 48);
+const BOOLEAN_TYPE: usize = QNAN | (0b010 << 48);
+const UNDEFINED_TYPE: usize = QNAN | (0b011 << 48);
+const NULL_TYPE: usize = QNAN | (0b100 << 48);
+
+#[allow(unused)]
+const RESERVED1_TYPE: usize = QNAN | (0b101 << 48);
+#[allow(unused)]
+const RESERVED2_TYPE: usize = QNAN | (0b110 << 48);
+#[allow(unused)]
+const RESERVED3_TYPE: usize = QNAN | (0b111 << 48);
+
+const POINTER_TYPE: usize = SIGN_BIT | QNAN;
+const OBJECT_TYPE: usize = POINTER_TYPE | (0b001 << 48);
+const STRING_TYPE: usize = POINTER_TYPE | (0b010 << 48);
+const SYMBOL_TYPE: usize = POINTER_TYPE | (0b011 << 48);
+const BIGINT_TYPE: usize = POINTER_TYPE | (0b100 << 48);
+
+#[allow(unused)]
+const RESERVED4_TYPE: usize = POINTER_TYPE | (0b101 << 48);
+#[allow(unused)]
+const RESERVED5_TYPE: usize = POINTER_TYPE | (0b110 << 48);
+#[allow(unused)]
+const RESERVED6_TYPE: usize = POINTER_TYPE | (0b111 << 48);
+
+const MASK_INT_PAYLOAD: usize = 0x00000000FFFFFFFF;
+const MASK_POINTER_PAYLOAD: usize = 0x0000FFFFFFFFFFFF;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, TryFromPrimitive)]
+#[repr(u16)]
+enum ValueTag {
+    Float64 = (DOUBLE_TYPE >> 48) as _,
+    Integer32 = (INTEGER_TYPE >> 48) as _,
+    Boolean = (BOOLEAN_TYPE >> 48) as _,
+    Undefined = (UNDEFINED_TYPE >> 48) as _,
+    Null = (NULL_TYPE >> 48) as _,
+    Object = (OBJECT_TYPE >> 48) as _,
+    String = (STRING_TYPE >> 48) as _,
+    Symbol = (SYMBOL_TYPE >> 48) as _,
+    BigInt = (BIGINT_TYPE >> 48) as _,
+    // Reserved1 = RESERVED1_TYPE,
+    // Reserved2 = RESERVED2_TYPE,
+    // Reserved3 = RESERVED3_TYPE,
+    // Reserved4 = RESERVED4_TYPE,
+    // Reserved5 = RESERVED5_TYPE,
+    // Reserved6 = RESERVED6_TYPE,
+}
+
+/// A Javascript value
+///
+/// Check the [`value`][`super::super`] module for more information.
+#[derive(Debug)]
+#[repr(transparent)]
+pub struct JsValue {
+    value: Cell<*mut ()>,
+}
+
+impl JsValue {
+    /// `null` - A null value, for when a value doesn't exist.
+    #[inline]
+    pub const fn null() -> Self {
+        Self {
+            value: Cell::new(sptr::invalid_mut(NULL_TYPE)),
+        }
+    }
+
+    /// `undefined` - An undefined value, for when a field or index doesn't exist
+    #[inline]
+    pub const fn undefined() -> Self {
+        Self {
+            value: Cell::new(sptr::invalid_mut(UNDEFINED_TYPE)),
+        }
+    }
+
+    /// `boolean` - A `true` / `false` value.
+    #[inline]
+    pub fn boolean(boolean: bool) -> Self {
+        let value = Self {
+            value: Cell::new(sptr::invalid_mut(usize::from(boolean) | BOOLEAN_TYPE)),
+        };
+        debug_assert!(value.is_boolean());
+        debug_assert_eq!(value.tag(), ValueTag::Boolean);
+        value
+    }
+
+    /// `integer32` - A 32-bit integer value, such as `42`.
+    #[inline]
+    pub fn integer32(integer32: i32) -> Self {
+        let value = Self {
+            value: Cell::new(sptr::invalid_mut(integer32 as u32 as usize | INTEGER_TYPE)),
+        };
+        debug_assert!(value.is_integer32());
+        debug_assert_eq!(value.tag(), ValueTag::Integer32);
+        value
+    }
+
+    /// `float64` - A 64-bit floating point number value, such as `3.1415`
+    #[inline]
+    pub fn float64(float64: f64) -> Self {
+        if float64.is_nan() {
+            return Self {
+                value: Cell::new(sptr::invalid_mut(CANONICALIZED_NAN)),
+            };
+        }
+
+        let value = Self {
+            value: Cell::new(sptr::invalid_mut(float64.to_bits() as usize)),
+        };
+        debug_assert!(value.is_float64());
+        debug_assert_eq!(value.tag(), ValueTag::Float64);
+        value
+    }
+
+    /// `String` - A [`JsString`] value, such as `"Hello, world"`.
+    #[inline]
+    pub fn string(string: JsString) -> Self {
+        let string = ManuallyDrop::new(string);
+        let pointer = unsafe { JsString::into_void_ptr(string) };
+        debug_assert_eq!(pointer.addr() & MASK_POINTER_PAYLOAD, pointer.addr());
+        let value = Self {
+            value: Cell::new(pointer.map_addr(|addr| addr | STRING_TYPE)),
+        };
+        debug_assert!(value.is_string());
+        debug_assert_eq!(value.tag(), ValueTag::String);
+        value
+    }
+
+    /// `BigInt` - A [`JsBigInt`] value, an arbitrarily large signed integer.
+    #[inline]
+    pub fn bigint(bigint: JsBigInt) -> Self {
+        let bigint = ManuallyDrop::new(bigint);
+        let pointer = unsafe { JsBigInt::into_void_ptr(bigint) };
+        debug_assert_eq!(pointer.addr() & MASK_POINTER_PAYLOAD, pointer.addr());
+        let value = Self {
+            value: Cell::new(pointer.map_addr(|addr| addr | BIGINT_TYPE)),
+        };
+        debug_assert!(value.is_bigint());
+        debug_assert_eq!(value.tag(), ValueTag::BigInt);
+        value
+    }
+
+    /// `Symbol` - A [`JsSymbol`] value.
+    #[inline]
+    pub fn symbol(symbol: JsSymbol) -> Self {
+        let symbol = ManuallyDrop::new(symbol);
+        let pointer = unsafe { JsSymbol::into_void_ptr(symbol) };
+        debug_assert_eq!(pointer.addr() & MASK_POINTER_PAYLOAD, pointer.addr());
+        let value = Self {
+            value: Cell::new(pointer.map_addr(|addr| addr | SYMBOL_TYPE)),
+        };
+        debug_assert!(value.is_symbol());
+        debug_assert_eq!(value.tag(), ValueTag::Symbol);
+        value
+    }
+
+    /// `Object` - A [`JsObject`], such as `Math`, represented by a binary tree of string keys to Javascript values.
+    #[inline]
+    pub fn object(object: JsObject) -> Self {
+        let object = ManuallyDrop::new(object);
+        let pointer = unsafe { JsObject::into_void_ptr(object) };
+        debug_assert_eq!(pointer.addr() & MASK_POINTER_PAYLOAD, pointer.addr());
+        debug_assert_eq!(OBJECT_TYPE & MASK_POINTER_PAYLOAD, 0);
+        let value = Self {
+            value: Cell::new(pointer.map_addr(|addr| addr | OBJECT_TYPE)),
+        };
+        debug_assert!(value.is_object());
+        debug_assert_eq!(value.tag(), ValueTag::Object);
+        value
+    }
+
+    /// Returns the internal [`bool`] if the value is a boolean, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_boolean(&self) -> Option<bool> {
+        if self.is_boolean() {
+            return Some(self.as_boolean_uncheched());
+        }
+
+        None
+    }
+
+    /// Returns the internal [`i32`] if the value is a 32-bit signed integer number, or
+    /// [`None`] otherwise.
+    pub fn as_integer32(&self) -> Option<i32> {
+        if self.is_integer32() {
+            return Some(self.as_integer32_uncheched());
+        }
+
+        None
+    }
+
+    /// Returns the internal [`f64`] if the value is a 64-bit floating-point number, or
+    /// [`None`] otherwise.
+    pub fn as_float64(&self) -> Option<f64> {
+        if self.is_float64() {
+            return Some(self.as_float64_unchecked());
+        }
+
+        None
+    }
+
+    /// Returns a reference to the internal [`JsString`] if the value is a string, or
+    /// [`None`] otherwise.
+    #[inline]
+    pub fn as_string(&self) -> Option<Ref<'_, JsString>> {
+        if self.is_string() {
+            return unsafe { Some(self.as_string_unchecked()) };
+        }
+
+        None
+    }
+
+    /// Returns a reference to the internal [`JsBigInt`] if the value is a big int, or
+    /// [`None`] otherwise.
+    pub fn as_bigint(&self) -> Option<Ref<'_, JsBigInt>> {
+        if self.is_bigint() {
+            return unsafe { Some(self.as_bigint_unchecked()) };
+        }
+
+        None
+    }
+
+    /// Returns a reference to the internal [`JsSymbol`] if the value is a symbol, or
+    /// [`None`] otherwise.
+    pub fn as_symbol(&self) -> Option<Ref<'_, JsSymbol>> {
+        if self.is_symbol() {
+            return unsafe { Some(self.as_symbol_unchecked()) };
+        }
+
+        None
+    }
+
+    /// Returns a reference to the internal [`JsObject`] if the value is an object, or
+    /// [`None`] otherwise.
+    pub fn as_object(&self) -> Option<Ref<'_, JsObject>> {
+        if self.is_object() {
+            return unsafe { Some(self.as_object_unchecked()) };
+        }
+
+        None
+    }
+
+    /// Returns true if the value is null.
+    #[inline]
+    pub fn is_null(&self) -> bool {
+        self.value.get().addr() == NULL_TYPE
+    }
+
+    /// Returns true if the value is undefined.
+    #[inline]
+    pub fn is_undefined(&self) -> bool {
+        self.value.get().addr() == UNDEFINED_TYPE
+    }
+
+    /// Returns true if the value is a boolean.
+    #[inline]
+    pub fn is_boolean(&self) -> bool {
+        self.value.get().addr() & TAG_MASK == BOOLEAN_TYPE
+    }
+
+    /// Returns true if the value is a 32-bit signed integer number.
+    pub fn is_integer32(&self) -> bool {
+        self.value.get().addr() & TAG_MASK == INTEGER_TYPE
+    }
+
+    /// Returns true if the value is a 64-bit floating-point number.
+    pub fn is_float64(&self) -> bool {
+        (self.value.get().addr() & !SIGN_BIT) <= QNAN
+    }
+
+    /// Returns true if the value is a 64-bit floating-point `NaN` number.
+    pub fn is_nan(&self) -> bool {
+        self.value.get().addr() == CANONICALIZED_NAN
+    }
+
+    /// Returns true if the value is a string.
+    #[inline]
+    pub fn is_string(&self) -> bool {
+        self.value.get().addr() & TAG_MASK == STRING_TYPE
+    }
+
+    /// Returns true if the value is a bigint.
+    #[inline]
+    pub fn is_bigint(&self) -> bool {
+        self.value.get().addr() & TAG_MASK == BIGINT_TYPE
+    }
+
+    /// Returns true if the value is a symbol.
+    pub fn is_symbol(&self) -> bool {
+        self.value.get().addr() & TAG_MASK == SYMBOL_TYPE
+    }
+
+    /// Returns true if the value is an object
+    #[inline]
+    pub fn is_object(&self) -> bool {
+        self.value.get().addr() & TAG_MASK == OBJECT_TYPE
+    }
+
+    /// Returns a [`JsVariant`] enum representing the current variant of the value.
+    ///
+    /// # Note
+    ///
+    /// More exotic implementations of [`JsValue`] cannot use direct references to
+    /// heap based types, so [`JsVariant`] instead returns [`Ref`]s on those cases.
+    pub fn variant(&self) -> JsVariant<'_> {
+        unsafe {
+            match self.tag() {
+                ValueTag::Null => JsVariant::Null,
+                ValueTag::Undefined => JsVariant::Undefined,
+                ValueTag::Integer32 => JsVariant::Integer32(self.as_integer32_uncheched()),
+                ValueTag::Float64 => JsVariant::Float64(self.as_float64_unchecked()),
+                ValueTag::Boolean => JsVariant::Boolean(self.as_boolean_uncheched()),
+                ValueTag::Object => JsVariant::Object(self.as_object_unchecked()),
+                ValueTag::String => JsVariant::String(self.as_string_unchecked()),
+                ValueTag::Symbol => JsVariant::Symbol(self.as_symbol_unchecked()),
+                ValueTag::BigInt => JsVariant::BigInt(self.as_bigint_unchecked()),
+            }
+        }
+    }
+
+    fn as_pointer(&self) -> *mut () {
+        self.value
+            .get()
+            .map_addr(|addr| addr & MASK_POINTER_PAYLOAD)
+    }
+
+    fn tag(&self) -> ValueTag {
+        if self.is_float64() {
+            return ValueTag::Float64;
+        }
+        let tag = ((self.value.get().addr() & TAG_MASK) >> 48) as u16;
+        ValueTag::try_from(tag).expect("Implementation must never construct an invalid tag")
+    }
+
+    fn as_boolean_uncheched(&self) -> bool {
+        (self.value.get().addr() & 0xFF) != 0
+    }
+
+    fn as_integer32_uncheched(&self) -> i32 {
+        (self.value.get().addr() & MASK_INT_PAYLOAD) as u32 as i32
+    }
+
+    fn as_float64_unchecked(&self) -> f64 {
+        f64::from_bits(self.value.get().addr() as u64)
+    }
+
+    /// Returns a reference to the boxed [`JsString`] without checking
+    /// if the tag of `self` is valid.
+    ///
+    /// # Safety
+    ///
+    /// Calling this method with a [`JsValue`] that doesn't box
+    /// a [`JsString`] is undefined behaviour.
+    unsafe fn as_string_unchecked(&self) -> Ref<'_, JsString> {
+        unsafe { Ref::new(JsString::from_void_ptr(self.as_pointer())) }
+    }
+
+    /// Returns a reference to the boxed [`JsBigInt`] without checking
+    /// if the tag of `self` is valid.
+    ///
+    /// # Safety
+    ///
+    /// Calling this method with a [`JsValue`] that doesn't box
+    /// a [`JsBigInt`] is undefined behaviour.
+    #[inline]
+    unsafe fn as_bigint_unchecked(&self) -> Ref<'_, JsBigInt> {
+        // SAFETY: The safety contract must be upheld by the caller
+        unsafe { Ref::new(JsBigInt::from_void_ptr(self.as_pointer())) }
+    }
+
+    /// Returns a reference to the boxed [`JsSymbol`] without checking
+    /// if the tag of `self` is valid.
+    ///
+    /// # Safety
+    ///
+    /// Calling this method with a [`JsValue`] that doesn't box
+    /// a [`JsSymbol`] is undefined behaviour.
+    unsafe fn as_symbol_unchecked(&self) -> Ref<'_, JsSymbol> {
+        unsafe { Ref::new(JsSymbol::from_void_ptr(self.as_pointer())) }
+    }
+
+    /// Returns a reference to the boxed [`JsObject`] without checking
+    /// if the tag of `self` is valid.
+    ///
+    /// # Safety
+    ///
+    /// Calling this method with a [`JsValue`] that doesn't box
+    /// a [`JsObject`] is undefined behaviour.
+    unsafe fn as_object_unchecked(&self) -> Ref<'_, JsObject> {
+        unsafe { Ref::new(JsObject::from_void_ptr(self.as_pointer())) }
+    }
+}
+
+impl Drop for JsValue {
+    #[inline]
+    fn drop(&mut self) {
+        unsafe {
+            match self.tag() {
+                ValueTag::Object => {
+                    ManuallyDrop::into_inner(JsObject::from_void_ptr(self.as_pointer()));
+                }
+                ValueTag::String => {
+                    ManuallyDrop::into_inner(JsString::from_void_ptr(self.as_pointer()));
+                }
+                ValueTag::Symbol => {
+                    ManuallyDrop::into_inner(JsSymbol::from_void_ptr(self.as_pointer()));
+                }
+                ValueTag::BigInt => {
+                    ManuallyDrop::into_inner(JsBigInt::from_void_ptr(self.as_pointer()));
+                }
+                _ => {}
+            }
+        }
+    }
+}
+
+impl Clone for JsValue {
+    #[inline]
+    fn clone(&self) -> Self {
+        unsafe {
+            match self.tag() {
+                ValueTag::Object => Self::new(self.as_object_unchecked().clone()),
+                ValueTag::String => Self::new(self.as_string_unchecked().clone()),
+                ValueTag::Symbol => Self::new(self.as_symbol_unchecked().clone()),
+                ValueTag::BigInt => Self::new(self.as_bigint_unchecked().clone()),
+                _ => Self {
+                    value: Cell::new(self.value.get()),
+                },
+            }
+        }
+    }
+}
+
+impl Finalize for JsValue {}
+
+unsafe impl Trace for JsValue {
+    unsafe fn trace(&self) {
+        if let Some(o) = self.as_object() {
+            // SAFETY: `self.as_object()` must always return a valid `JsObject
+            unsafe {
+                o.trace();
+            }
+        }
+    }
+
+    unsafe fn root(&self) {
+        if self.tag() == ValueTag::Object {
+            // SAFETY: Implementors of `PointerType` must guarantee the
+            // safety of both `from_void_ptr` and `into_void_ptr`
+            unsafe {
+                let o = JsObject::from_void_ptr(self.as_pointer());
+                o.root();
+                self.value
+                    .set(JsObject::into_void_ptr(o).map_addr(|addr| addr | OBJECT_TYPE));
+            }
+        }
+    }
+
+    unsafe fn unroot(&self) {
+        if self.tag() == ValueTag::Object {
+            // SAFETY: Implementors of `PointerType` must guarantee the
+            // safety of both `from_void_ptr` and `into_void_ptr`
+            unsafe {
+                let o = JsObject::from_void_ptr(self.as_pointer());
+                o.unroot();
+                self.value
+                    .set(JsObject::into_void_ptr(o).map_addr(|addr| addr | OBJECT_TYPE));
+            }
+        }
+    }
+
+    #[inline]
+    fn finalize_glue(&self) {
+        if let Some(o) = self.as_object() {
+            o.finalize_glue();
+        }
+    }
+}
+
+/// Represents a reference to a boxed pointer type inside a [`JsValue`]
+///
+/// This is exclusively used to return references to [`JsString`], [`JsObject`],
+/// [`JsSymbol`] and [`JsBigInt`], since some [`JsValue`] implementations makes
+/// returning proper references difficult.
+/// It is mainly returned by the [`JsValue::variant`] method and the
+/// `as_` methods for checked casts to pointer types.
+///
+/// [`Ref`] implements [`Deref`][`std::ops::Deref`], which facilitates conversion
+/// to a proper [`reference`] by using the `ref` keyword or the
+/// [`Option::as_deref`][`std::option::Option::as_deref`] method.
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Ref<'a, T> {
+    inner: ManuallyDrop<T>,
+    _marker: PhantomData<&'a T>,
+}
+
+impl<T> Ref<'_, T> {
+    #[inline]
+    fn new(inner: ManuallyDrop<T>) -> Self {
+        Self {
+            inner,
+            _marker: PhantomData,
+        }
+    }
+}
+
+// Lift `Ref` over `AsRef`, since implementing `AsRef<T>` would override the
+// `as_ref` implementations of `T`.
+impl<U, T> AsRef<U> for Ref<'_, T>
+where
+    T: AsRef<U>,
+{
+    #[inline]
+    fn as_ref(&self) -> &U {
+        <T as AsRef<U>>::as_ref(&*self)
+    }
+}
+
+impl<T> std::ops::Deref for Ref<'_, T> {
+    type Target = T;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        &*self.inner
+    }
+}
+
+impl<T: PartialEq> PartialEq<T> for Ref<'_, T> {
+    #[inline]
+    fn eq(&self, other: &T) -> bool {
+        &**self == other
+    }
+}
+
+impl<T> std::borrow::Borrow<T> for Ref<'_, T> {
+    #[inline]
+    fn borrow(&self) -> &T {
+        &**self
+    }
+}
+
+#[cfg(test)]
+mod tests_nan_box {
+    use crate::object::ObjectData;
+
+    use super::*;
+
+    #[test]
+    fn bigint() {
+        let value = JsValue::new(JsBigInt::new(12345));
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+        assert!(!value.is_integer32());
+        assert!(!value.is_float64());
+        assert!(!value.is_boolean());
+        assert!(!value.is_object());
+        assert!(!value.is_string());
+        assert!(!value.is_symbol());
+
+        assert!(value.is_bigint());
+
+        let bigint = value.as_bigint().unwrap();
+
+        assert_eq!(&bigint, &JsBigInt::new(12345));
+    }
+
+    #[test]
+    fn symbol() {
+        let value = JsValue::new(JsSymbol::new(Some("description...".into())));
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+        assert!(!value.is_integer32());
+        assert!(!value.is_float64());
+        assert!(!value.is_boolean());
+        assert!(!value.is_object());
+        assert!(!value.is_string());
+
+        assert!(value.is_symbol());
+
+        let symbol = value.as_symbol().unwrap();
+
+        assert_eq!(symbol.description(), Some("description...".into()));
+    }
+
+    #[test]
+    fn string() {
+        let value = JsValue::new("I am a string :)");
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+        assert!(!value.is_integer32());
+        assert!(!value.is_float64());
+        assert!(!value.is_boolean());
+        assert!(!value.is_object());
+
+        assert!(value.is_string());
+
+        let string = value.as_string().unwrap();
+
+        assert_eq!(JsString::refcount(&string), Some(1));
+
+        assert_eq!(*string, "I am a string :)");
+    }
+
+    #[test]
+    fn object() {
+        //let context = Context::default();
+
+        let o1 = JsObject::from_proto_and_data(None, ObjectData::ordinary());
+
+        // let value = JsValue::new(context.construct_object());
+        let value = JsValue::new(o1.clone());
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+        assert!(!value.is_integer32());
+        assert!(!value.is_float64());
+        assert!(!value.is_boolean());
+
+        assert!(value.is_object());
+
+        let o2 = value.as_object().unwrap();
+        assert!(JsObject::equals(&o1, &o2));
+    }
+
+    #[test]
+    fn boolean() {
+        let value = JsValue::new(true);
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+        assert!(!value.is_integer32());
+        assert!(!value.is_float64());
+
+        assert!(value.is_boolean());
+        assert_eq!(value.as_boolean(), Some(true));
+
+        let value = JsValue::new(false);
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+        assert!(!value.is_integer32());
+        assert!(!value.is_float64());
+
+        assert!(value.is_boolean());
+        assert_eq!(value.as_boolean(), Some(false));
+    }
+
+    #[test]
+    fn float64() {
+        let value = JsValue::new(1.3);
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+        assert!(!value.is_integer32());
+
+        assert!(value.is_float64());
+        assert_eq!(value.as_float64(), Some(1.3));
+
+        let value = JsValue::new(f64::MAX);
+        assert!(value.is_float64());
+        assert_eq!(value.as_float64(), Some(f64::MAX));
+
+        let value = JsValue::new(f64::MIN);
+        assert!(value.is_float64());
+        assert_eq!(value.as_float64(), Some(f64::MIN));
+
+        let value = JsValue::nan();
+        assert!(value.is_float64());
+        assert!(value.as_float64().unwrap().is_nan());
+
+        let value = JsValue::new(12345);
+        assert!(!value.is_float64());
+        assert_eq!(value.as_float64(), None);
+
+        let value = JsValue::undefined();
+        assert!(!value.is_float64());
+        assert_eq!(value.as_float64(), None);
+
+        let value = JsValue::null();
+        assert!(!value.is_float64());
+        assert_eq!(value.as_float64(), None);
+    }
+
+    #[test]
+    fn undefined() {
+        let value = JsValue::undefined();
+
+        println!("{:?}", value);
+        println!("{:?}", UNDEFINED_TYPE);
+
+        assert!(value.is_undefined());
+    }
+
+    #[test]
+    fn null() {
+        let value = JsValue::null();
+
+        assert!(value.is_null());
+        assert!(value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+    }
+
+    #[test]
+    fn integer32() {
+        let value = JsValue::new(-0xcafe);
+
+        assert!(!value.is_null());
+        assert!(!value.is_null_or_undefined());
+        assert!(!value.is_undefined());
+
+        assert!(value.is_integer32());
+
+        assert_eq!(value.as_integer32(), Some(-0xcafe));
+
+        let value = JsValue::null();
+        assert_eq!(value.as_integer32(), None);
+    }
+}
diff --git a/boa_engine/src/value/tests.rs b/boa_engine/src/value/tests.rs
index dce5bb5a0b..e80622b259 100644
--- a/boa_engine/src/value/tests.rs
+++ b/boa_engine/src/value/tests.rs
@@ -694,7 +694,7 @@ mod cyclic_conversions {
 
         let value = forward_val(&mut context, src).unwrap();
         let result = value.as_string().unwrap();
-        assert_eq!(result, "[[],[]]",);
+        assert_eq!(*result, "[[],[]]",);
     }
 
     // These tests don't throw errors. Instead we mirror Chrome / Firefox behavior for these
@@ -711,7 +711,7 @@ mod cyclic_conversions {
 
         let value = forward_val(&mut context, src).unwrap();
         let result = value.as_string().unwrap();
-        assert_eq!(result, "");
+        assert_eq!(*result, "");
     }
 
     #[test]
diff --git a/boa_engine/src/value/type.rs b/boa_engine/src/value/type.rs
index 61e100bae6..fbf6472db3 100644
--- a/boa_engine/src/value/type.rs
+++ b/boa_engine/src/value/type.rs
@@ -1,4 +1,4 @@
-use super::JsValue;
+use super::{JsValue, JsVariant};
 
 /// Possible types of values as defined at <https://tc39.es/ecma262/#sec-typeof-operator>.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -21,15 +21,15 @@ impl JsValue {
     ///
     /// Check [`JsValue::type_of`] if you need to call the `typeof` operator.
     pub fn get_type(&self) -> Type {
-        match *self {
-            Self::Rational(_) | Self::Integer(_) => Type::Number,
-            Self::String(_) => Type::String,
-            Self::Boolean(_) => Type::Boolean,
-            Self::Symbol(_) => Type::Symbol,
-            Self::Null => Type::Null,
-            Self::Undefined => Type::Undefined,
-            Self::BigInt(_) => Type::BigInt,
-            Self::Object(_) => Type::Object,
+        match self.variant() {
+            JsVariant::Float64(_) | JsVariant::Integer32(_) => Type::Number,
+            JsVariant::String(_) => Type::String,
+            JsVariant::Boolean(_) => Type::Boolean,
+            JsVariant::Symbol(_) => Type::Symbol,
+            JsVariant::Null => Type::Null,
+            JsVariant::Undefined => Type::Undefined,
+            JsVariant::BigInt(_) => Type::BigInt,
+            JsVariant::Object(_) => Type::Object,
         }
     }
 }
diff --git a/boa_engine/src/vm/code_block.rs b/boa_engine/src/vm/code_block.rs
index efe70b5fba..76bfbafc0c 100644
--- a/boa_engine/src/vm/code_block.rs
+++ b/boa_engine/src/vm/code_block.rs
@@ -20,7 +20,7 @@ use crate::{
     syntax::ast::node::FormalParameterList,
     vm::call_frame::GeneratorResumeKind,
     vm::{call_frame::FinallyReturn, CallFrame, Opcode},
-    Context, JsResult, JsValue,
+    Context, JsResult, JsValue, value::JsVariant,
 };
 use boa_gc::{Cell, Finalize, Gc, Trace};
 use boa_interner::{Interner, Sym, ToInternedString};
@@ -749,7 +749,7 @@ impl JsObject {
                 let args = if code.params.parameters.len() > args.len() {
                     let mut v = args.to_vec();
                     v.extend(vec![
-                        JsValue::Undefined;
+                        JsValue::undefined();
                         code.params.parameters.len() - args.len()
                     ]);
                     v
@@ -872,7 +872,7 @@ impl JsObject {
                 let args = if code.params.parameters.len() > args.len() {
                     let mut v = args.to_vec();
                     v.extend(vec![
-                        JsValue::Undefined;
+                        JsValue::undefined();
                         code.params.parameters.len() - args.len()
                     ]);
                     v
@@ -989,7 +989,7 @@ impl JsObject {
                 let mut args = if code.params.parameters.len() > args.len() {
                     let mut v = args.to_vec();
                     v.extend(vec![
-                        JsValue::Undefined;
+                        JsValue::undefined();
                         code.params.parameters.len() - args.len()
                     ]);
                     v
@@ -1124,7 +1124,7 @@ impl JsObject {
                 let mut args = if code.params.parameters.len() > args.len() {
                     let mut v = args.to_vec();
                     v.extend(vec![
-                        JsValue::Undefined;
+                        JsValue::undefined();
                         code.params.parameters.len() - args.len()
                     ]);
                     v
@@ -1238,10 +1238,10 @@ impl JsObject {
                 let constructor = *constructor;
                 drop(object);
 
-                match function(this_target, args, context)? {
-                    JsValue::Object(ref o) => Ok(o.clone()),
+                match function(this_target, args, context)?.variant() {
+                    JsVariant::Object(o) => Ok(o.clone()),
                     val => {
-                        if constructor.expect("hmm").is_base() || val.is_undefined() {
+                        if constructor.expect("hmm").is_base() || matches!(val, JsVariant::Undefined) {
                             create_this(context)
                         } else {
                             context.throw_type_error(
@@ -1262,10 +1262,10 @@ impl JsObject {
                 let constructor = *constructor;
                 drop(object);
 
-                match (function)(this_target, args, captures, context)? {
-                    JsValue::Object(ref o) => Ok(o.clone()),
+                match (function)(this_target, args, captures, context)?.variant() {
+                    JsVariant::Object(o) => Ok(o.clone()),
                     val => {
-                        if constructor.expect("hmma").is_base() || val.is_undefined() {
+                        if constructor.expect("hmma").is_base() || matches!(val, JsVariant::Undefined) {
                             create_this(context)
                         } else {
                             context.throw_type_error(
@@ -1369,7 +1369,7 @@ impl JsObject {
                 let args = if code.params.parameters.len() > args.len() {
                     let mut v = args.to_vec();
                     v.extend(vec![
-                        JsValue::Undefined;
+                        JsValue::undefined();
                         code.params.parameters.len() - args.len()
                     ]);
                     v
diff --git a/boa_engine/src/vm/mod.rs b/boa_engine/src/vm/mod.rs
index f17a008928..2a5ab4da0d 100644
--- a/boa_engine/src/vm/mod.rs
+++ b/boa_engine/src/vm/mod.rs
@@ -12,7 +12,7 @@ use crate::{
     environments::EnvironmentSlots,
     object::{FunctionBuilder, JsFunction, JsObject, ObjectData, PrivateElement},
     property::{DescriptorKind, PropertyDescriptor, PropertyDescriptorBuilder, PropertyKey},
-    value::Numeric,
+    value::{JsVariant, Numeric},
     vm::{
         call_frame::CatchAddresses,
         code_block::{initialize_instance_elements, Readable},
@@ -229,17 +229,17 @@ impl Context {
                     self.vm.push(class);
                     self.vm.push(proto);
                 } else if superclass.is_null() {
-                    self.vm.push(JsValue::Null);
+                    self.vm.push(JsValue::null());
                 } else {
                     return self.throw_type_error("superclass must be a constructor");
                 }
             }
             Opcode::SetClassPrototype => {
                 let prototype_value = self.vm.pop();
-                let prototype = match &prototype_value {
-                    JsValue::Object(proto) => Some(proto.clone()),
-                    JsValue::Null => None,
-                    JsValue::Undefined => {
+                let prototype = match prototype_value.variant() {
+                    JsVariant::Object(proto) => Some(proto.clone()),
+                    JsVariant::Null => None,
+                    JsVariant::Undefined => {
                         Some(self.intrinsics().constructors().object().prototype.clone())
                     }
                     _ => unreachable!(),
@@ -484,7 +484,7 @@ impl Context {
                         .into();
                     self.global_bindings_mut().entry(key).or_insert(
                         PropertyDescriptor::builder()
-                            .value(JsValue::Undefined)
+                            .value(JsValue::undefined())
                             .writable(true)
                             .enumerable(true)
                             .configurable(true)
@@ -494,7 +494,7 @@ impl Context {
                     self.realm.environments.put_value_if_uninitialized(
                         binding_locator.environment_index(),
                         binding_locator.binding_index(),
-                        JsValue::Undefined,
+                        JsValue::undefined(),
                     );
                 }
             }
@@ -526,7 +526,7 @@ impl Context {
                 self.realm.environments.put_value(
                     binding_locator.environment_index(),
                     binding_locator.binding_index(),
-                    JsValue::Undefined,
+                    JsValue::undefined(),
                 );
             }
             Opcode::DefInitLet | Opcode::DefInitConst | Opcode::DefInitArg => {
@@ -1530,10 +1530,10 @@ impl Context {
                     if let Some(proto) = home.__get_prototype_of__(self)? {
                         self.vm.push(JsValue::from(proto));
                     } else {
-                        self.vm.push(JsValue::Null);
+                        self.vm.push(JsValue::null());
                     }
                 } else {
-                    self.vm.push(JsValue::Null);
+                    self.vm.push(JsValue::null());
                 };
             }
             Opcode::SuperCall => {
@@ -1739,8 +1739,8 @@ impl Context {
                 let func = self.vm.pop();
                 let this = self.vm.pop();
 
-                let object = match func {
-                    JsValue::Object(ref object) if object.is_callable() => object.clone(),
+                let object = match func.variant() {
+                    JsVariant::Object(object) if object.is_callable() => object.clone(),
                     _ => return self.throw_type_error("not a callable function"),
                 };
 
@@ -1755,7 +1755,7 @@ impl Context {
                             crate::builtins::eval::Eval::perform_eval(x, true, strict, self)?;
                         self.vm.push(result);
                     } else {
-                        self.vm.push(JsValue::Undefined);
+                        self.vm.push(JsValue::undefined());
                     }
                 } else {
                     let result = object.__call__(&this, &arguments, self)?;
@@ -1782,8 +1782,8 @@ impl Context {
                 let func = self.vm.pop();
                 let this = self.vm.pop();
 
-                let object = match func {
-                    JsValue::Object(ref object) if object.is_callable() => object.clone(),
+                let object = match func.variant() {
+                    JsVariant::Object(object) if object.is_callable() => object.clone(),
                     _ => return self.throw_type_error("not a callable function"),
                 };
 
@@ -1798,7 +1798,7 @@ impl Context {
                             crate::builtins::eval::Eval::perform_eval(x, true, strict, self)?;
                         self.vm.push(result);
                     } else {
-                        self.vm.push(JsValue::Undefined);
+                        self.vm.push(JsValue::undefined());
                     }
                 } else {
                     let result = object.__call__(&this, &arguments, self)?;
@@ -1819,8 +1819,8 @@ impl Context {
                 let func = self.vm.pop();
                 let this = self.vm.pop();
 
-                let object = match func {
-                    JsValue::Object(ref object) if object.is_callable() => object.clone(),
+                let object = match func.variant() {
+                    JsVariant::Object(object) if object.is_callable() => object,
                     _ => return self.throw_type_error("not a callable function"),
                 };
 
@@ -1848,8 +1848,8 @@ impl Context {
                 let func = self.vm.pop();
                 let this = self.vm.pop();
 
-                let object = match func {
-                    JsValue::Object(ref object) if object.is_callable() => object.clone(),
+                let object = match func.variant() {
+                    JsVariant::Object(object) if object.is_callable() => object.clone(),
                     _ => return self.throw_type_error("not a callable function"),
                 };
 
@@ -1872,7 +1872,7 @@ impl Context {
                 let result = func
                     .as_constructor()
                     .ok_or_else(|| self.construct_type_error("not a constructor"))
-                    .and_then(|cons| cons.__construct__(&arguments, cons, self))?;
+                    .and_then(|cons| cons.__construct__(&arguments, &cons, self))?;
 
                 self.vm.push(result);
             }
@@ -1897,7 +1897,7 @@ impl Context {
                 let result = func
                     .as_constructor()
                     .ok_or_else(|| self.construct_type_error("not a constructor"))
-                    .and_then(|cons| cons.__construct__(&arguments, cons, self))?;
+                    .and_then(|cons| cons.__construct__(&arguments, &cons, self))?;
 
                 self.vm.push(result);
             }
@@ -2054,7 +2054,7 @@ impl Context {
                 let iterator = iterator.as_object().expect("iterator was not an object");
                 if !done {
                     let iterator_record = IteratorRecord::new(iterator.clone(), next_method, done);
-                    iterator_record.close(Ok(JsValue::Null), self)?;
+                    iterator_record.close(Ok(JsValue::null()), self)?;
                 }
             }
             Opcode::IteratorToArray => {
@@ -2309,7 +2309,7 @@ impl Context {
                         self.vm.frame_mut().pc = done_address as usize;
                         let iterator_record =
                             IteratorRecord::new(iterator.clone(), next_method, done);
-                        iterator_record.close(Ok(JsValue::Undefined), self)?;
+                        iterator_record.close(Ok(JsValue::undefined()), self)?;
                         let error =
                             self.construct_type_error("iterator does not have a throw method");
                         return Err(error);
@@ -2582,7 +2582,7 @@ impl Context {
                 }
                 Ok(ShouldExit::False) => {}
                 Ok(ShouldExit::Yield) => {
-                    let result = self.vm.stack.pop().unwrap_or(JsValue::Undefined);
+                    let result = self.vm.stack.pop().unwrap_or(JsValue::undefined());
                     return Ok((result, ReturnType::Yield));
                 }
                 Err(e) => {
diff --git a/boa_engine/src/vm/tests.rs b/boa_engine/src/vm/tests.rs
index 8a5fda7be0..cbca50d489 100644
--- a/boa_engine/src/vm/tests.rs
+++ b/boa_engine/src/vm/tests.rs
@@ -62,7 +62,7 @@ fn multiple_catches() {
 
     assert_eq!(
         Context::default().eval(source.as_bytes()),
-        Ok(JsValue::Undefined)
+        Ok(JsValue::undefined())
     );
 }
 
diff --git a/boa_examples/src/bin/modulehandler.rs b/boa_examples/src/bin/modulehandler.rs
index e482447e33..dc932028a9 100644
--- a/boa_examples/src/bin/modulehandler.rs
+++ b/boa_examples/src/bin/modulehandler.rs
@@ -46,7 +46,7 @@ fn require(_: &JsValue, args: &[JsValue], ctx: &mut Context) -> JsResult<JsValue
     let buffer = read_to_string(libfile);
     if let Err(..) = buffer {
         println!("Error: {}", buffer.unwrap_err());
-        Ok(JsValue::Rational(-1.0))
+        Ok(JsValue::from(-1.0))
     } else {
         // Load and parse the module source
         ctx.eval(&buffer.unwrap()).unwrap();
diff --git a/boa_tester/src/exec/js262.rs b/boa_tester/src/exec/js262.rs
index f6ad73dd21..2190cced2e 100644
--- a/boa_tester/src/exec/js262.rs
+++ b/boa_tester/src/exec/js262.rs
@@ -64,7 +64,7 @@ fn detach_array_buffer(
     let key = args.get_or_undefined(1);
 
     // 3. If SameValue(arrayBuffer.[[ArrayBufferDetachKey]], key) is false, throw a TypeError exception.
-    if !JsValue::same_value(&array_buffer.array_buffer_detach_key, key) {
+    if !JsValue::same_value(&array_buffer.array_buffer_detach_key, &key) {
         return context.throw_type_error("Cannot detach array buffer with different key");
     }