diff --git a/core/engine/src/value/conversions/serde_json.rs b/core/engine/src/value/conversions/serde_json.rs
index 104d928e7c..95bbd5e884 100644
--- a/core/engine/src/value/conversions/serde_json.rs
+++ b/core/engine/src/value/conversions/serde_json.rs
@@ -124,22 +124,33 @@ impl JsValue {
                 .with_message("cannot convert bigint to JSON")
                 .into()),
             Self::Object(obj) => {
+                let value_by_prop_key = |property_key, context: &mut Context| {
+                    obj.borrow()
+                        .properties()
+                        .get(&property_key)
+                        .and_then(|x| x.value().map(|val| val.to_json(context)))
+                        .unwrap_or(Ok(Value::Null))
+                };
+
                 if obj.is_array() {
                     let len = obj.length_of_array_like(context)?;
                     let mut arr = Vec::with_capacity(len as usize);
 
-                    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)
-                        });
-                        arr.push(val.to_json(context)?);
+                        let val = value_by_prop_key(k.into(), context)?;
+                        arr.push(val);
                     }
 
                     Ok(Value::Array(arr))
                 } else {
                     let mut map = Map::new();
+
+                    for index in obj.borrow().properties().index_property_keys() {
+                        let key = index.to_string();
+                        let value = value_by_prop_key(index.into(), context)?;
+                        map.insert(key, value);
+                    }
+
                     for property_key in obj.borrow().properties().shape.keys() {
                         let key = match &property_key {
                             PropertyKey::String(string) => string.to_std_string_escaped(),
@@ -150,17 +161,7 @@ impl JsValue {
                                     .into())
                             }
                         };
-
-                        let value = match obj
-                            .borrow()
-                            .properties()
-                            .get(&property_key)
-                            .and_then(|x| x.value().cloned())
-                        {
-                            Some(val) => val.to_json(context)?,
-                            None => Value::Null,
-                        };
-
+                        let value = value_by_prop_key(property_key, context)?;
                         map.insert(key, value);
                     }
 
@@ -181,7 +182,7 @@ mod tests {
     use serde_json::json;
 
     use crate::object::JsArray;
-    use crate::JsValue;
+    use crate::{js_string, JsValue};
     use crate::{run_test_actions, TestAction};
 
     #[test]
@@ -200,7 +201,10 @@ mod tests {
                     -45,
                     {},
                     true
-                ]
+                ],
+                "7.3": "random text",
+                "100": 1000,
+                "24": 42
             }
         "#};
 
@@ -217,6 +221,14 @@ mod tests {
             assert_eq!(obj.get(js_str!("age"), ctx).unwrap(), 43_i32.into());
             assert_eq!(obj.get(js_str!("minor"), ctx).unwrap(), false.into());
             assert_eq!(obj.get(js_str!("adult"), ctx).unwrap(), true.into());
+
+            assert_eq!(
+                obj.get(js_str!("7.3"), ctx).unwrap(),
+                js_string!("random text").into()
+            );
+            assert_eq!(obj.get(js_str!("100"), ctx).unwrap(), 1000.into());
+            assert_eq!(obj.get(js_str!("24"), ctx).unwrap(), 42.into());
+
             {
                 let extra = obj.get(js_str!("extra"), ctx).unwrap();
                 let extra = extra.as_object().unwrap();