diff --git a/boa/src/builtins/map/mod.rs b/boa/src/builtins/map/mod.rs
index 9912d18844..e1708cfe4d 100644
--- a/boa/src/builtins/map/mod.rs
+++ b/boa/src/builtins/map/mod.rs
@@ -1,4 +1,4 @@
-//! This module implements the global `Map` objest.
+//! This module implements the global `Map` object.
 //!
 //! The JavaScript `Map` class is a global object that is used in the construction of maps; which
 //! are high-level, key-value stores.
@@ -31,6 +31,7 @@ use map_iterator::MapIterator;
 use self::ordered_map::MapLock;
 
 use super::JsArgs;
+use num_traits::Zero;
 
 pub mod ordered_map;
 #[cfg(test)]
@@ -248,7 +249,17 @@ impl Map {
 
         let size = if let Some(object) = this.as_object() {
             if let Some(map) = object.borrow_mut().as_map_mut() {
-                map.insert(key.clone(), value.clone());
+                let key = match key {
+                    JsValue::Rational(r) => {
+                        if r.is_zero() {
+                            JsValue::Rational(0f64)
+                        } else {
+                            key.clone()
+                        }
+                    }
+                    _ => key.clone(),
+                };
+                map.insert(key, value.clone());
                 map.len()
             } else {
                 return Err(context.construct_type_error("'this' is not a Map"));
@@ -309,6 +320,19 @@ impl Map {
     ) -> JsResult<JsValue> {
         let key = args.get_or_undefined(0);
 
+        const JS_ZERO: &JsValue = &JsValue::Rational(0f64);
+
+        let key = match key {
+            JsValue::Rational(r) => {
+                if r.is_zero() {
+                    JS_ZERO
+                } else {
+                    key
+                }
+            }
+            _ => key,
+        };
+
         if let JsValue::Object(ref object) = this {
             let object = object.borrow();
             if let Some(map) = object.as_map_ref() {
@@ -333,11 +357,23 @@ impl Map {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-map.prototype.clear
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/clear
-    pub(crate) fn clear(this: &JsValue, _: &[JsValue], _: &mut Context) -> JsResult<JsValue> {
-        this.set_data(ObjectData::map(OrderedMap::new()));
-
+    pub(crate) fn clear(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
+        // 1. Let M be the this value.
+        // 2. Perform ? RequireInternalSlot(M, [[MapData]]).
+        // 3. Let entries be the List that is M.[[MapData]].
+        // 4. For each Record { [[Key]], [[Value]] } p of entries, do
+        // a. Set p.[[Key]] to empty.
+        // b. Set p.[[Value]] to empty.
         Self::set_size(this, 0);
-
+        if let Some(object) = this.as_object() {
+            if let Some(map) = object.borrow_mut().as_map_mut() {
+                map.clear();
+            } else {
+                return context.throw_type_error("'this' is not a Map");
+            }
+        } else {
+            return context.throw_type_error("'this' is not a Map");
+        }
         Ok(JsValue::undefined())
     }
 
@@ -388,6 +424,12 @@ impl Map {
         }
 
         let callback_arg = &args[0];
+
+        if !callback_arg.is_function() {
+            let name = callback_arg.to_string(context)?;
+            return context.throw_type_error(format!("{} is not a function", name));
+        }
+
         let this_arg = args.get_or_undefined(1);
 
         let mut index = 0;
diff --git a/boa/src/builtins/map/ordered_map.rs b/boa/src/builtins/map/ordered_map.rs
index dc97d5c397..3fbd0d6d0d 100644
--- a/boa/src/builtins/map/ordered_map.rs
+++ b/boa/src/builtins/map/ordered_map.rs
@@ -142,6 +142,11 @@ impl<V> OrderedMap<V> {
         }
     }
 
+    pub fn clear(&mut self) {
+        self.map.clear();
+        self.map.shrink_to_fit();
+    }
+
     /// Return a reference to the value stored for `key`, if it is present,
     /// else `None`.
     ///