WIP - Update JSON Global (#129)

* Added create_constructor method

* Updated global to use json::create_constructor method

* unassigned var is undefined (#125)

* Unassigned variables are set to `undefined` not `null`

Fixes #113

* Rust tests for `var x` and `let x` default to undefined

* CHANGELOG for issue #113 fix + add tests/js/test.js to gitignore.

* fixing PR benchmarks (#132)

* fixing PR benchmarks

* Push after rebase

* Updated import order

* Formatting

CHANGELOG.md

@@ -26,6 +26,11 @@ Bug fixes:
   Unassigned variables have default of undefined (@pop)
 - Tidy up Globals being added to Global Object. Thanks @DomParfitt
 
+Bug fixes:
+
+- [BUG #113](https://github.com/jasonwilliams/boa/issues/113):
+  Unassigned variables have default of undefined (@pop)
+
 # 0.4.0 (2019-09-25)
 
 v0.4.0 brings quite a big release. The biggest feature to land is the support of regular expressions.  

src/lib/js/json.rs

@@ -1,5 +1,6 @@
 use crate::exec::Interpreter;
 use crate::js::function::NativeFunctionData;
+use crate::js::object::{Object, ObjectKind, PROTOTYPE};
 /// The JSON Object
 /// <https://tc39.github.io/ecma262/#sec-json-object>
 use crate::js::value::{to_value, ResultValue, Value, ValueData};
@@ -27,14 +28,15 @@ pub fn stringify(_: &Value, args: &[Value], _: &mut Interpreter) -> ResultValue
 }
 
 /// Create a new `JSON` object
-pub fn _create(global: &Value) -> Value {
-    let object = ValueData::new_obj(Some(global));
-    object.set_field_slice("stringify", to_value(stringify as NativeFunctionData));
-    object.set_field_slice("parse", to_value(parse as NativeFunctionData));
-    object
-}
+pub fn create_constructor(global: &Value) -> Value {
+    let mut json = Object::default();
+    json.kind = ObjectKind::Ordinary;
+
+    let prototype = ValueData::new_obj(Some(global));
+    prototype.set_field_slice("parse", to_value(parse as NativeFunctionData));
+    prototype.set_field_slice("stringify", to_value(stringify as NativeFunctionData));
 
-/// Initialise the global object with the `JSON` object
-pub fn init(global: &Value) {
-    global.set_field_slice("JSON", _create(global));
+    let json_value = to_value(json);
+    json_value.set_field_slice(PROTOTYPE, prototype);
+    json_value
 }

src/lib/realm.rs

@@ -54,12 +54,12 @@ impl Realm {
         // Create intrinsics, add global objects here
         object::init(global);
         function::init(global);
-        json::init(global);
 
         global.set_field_slice("String", string::create_constructor(global));
         global.set_field_slice("RegExp", regexp::create_constructor(global));
         global.set_field_slice("Array", array::create_constructor(global));
         global.set_field_slice("Boolean", boolean::create_constructor(global));
+        global.set_field_slice("JSON", json::create_constructor(global));
         global.set_field_slice("Math", math::create_constructor(global));
         global.set_field_slice("console", console::create_constructor(global));
     }