Implement Symbol.unscopables on OrderedCollection (#6215)

* Implement 'Symbol.unscopables' on 'OrderedCollection'.

* Replace impl. with that of the Array.prototype's unscopable object.

* Add CHANGELOG entry.

* Update package.json change from separate branch.

Accidentally included a package.json change from another branch that has not yet been merged.

* Update link in comment.

* Move CHANGELOG entry from 'Enhancements' to 'Fixed'.

* Update link in comment.

CHANGELOG.md

@@ -7,8 +7,7 @@
 * None
 
 ### Fixed
-* <How to hit and notice issue? what was the impact?> ([#????](https://github.com/realm/realm-js/issues/????), since v?.?.?)
-* None
+* `Symbol.unscopables` has been implemented on the base class of `Realm.Results`, `Realm.List`, and `Realm.Set`. ([#6215](https://github.com/realm/realm-js/pull/6215))
 
 ### Compatibility
 * React Native >= v0.71.4

packages/realm/src/OrderedCollection.ts

@@ -178,6 +178,12 @@ export abstract class OrderedCollection<T = unknown, EntryType extends [unknown,
       writable: false,
       value: mixedToBinding.bind(undefined, realm.internal),
     });
+    // See https://tc39.es/ecma262/multipage/indexed-collections.html#sec-array.prototype-@@unscopables
+    Object.defineProperty(this, Symbol.unscopables, {
+      enumerable: false,
+      configurable: true,
+      writable: false,
+    });
     return proxied;
   }
 
@@ -626,6 +632,12 @@ export abstract class OrderedCollection<T = unknown, EntryType extends [unknown,
     return this.values();
   }
 
+  /**
+   * An Object whose truthy properties are properties that are excluded from the 'with'
+   * environment bindings of the associated objects.
+   */
+  readonly [Symbol.unscopables] = Array.prototype[Symbol.unscopables];
+
   // Other methods
 
   // TODO: Implement this method