webidl/ecmascript-binding/interface-object-set-receiver.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>window.Interface is defined on [[Set]] receiver</title>
<link rel="help" href="https://webidl.spec.whatwg.org/#define-the-global-property-references">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
"use strict";
const testValue = Object.freeze(function() {});

test(() => {
  window.Window = testValue;
  assert_false(window.propertyIsEnumerable("Window"));

  window.History = testValue;
  assert_false(window.propertyIsEnumerable("History"));

  window.HTMLDivElement = testValue;
  assert_false(window.propertyIsEnumerable("HTMLDivElement"))
}, "Direct [[Set]] preserves [[Enumerable]]: false property attribute");

test(() => {
  const heir = Object.create(window);

  heir.Location = testValue;
  assert_equals(heir.Location, testValue);
  assert_not_equals(window.Location, testValue);

  heir.HTMLDocument = testValue;
  assert_equals(heir.HTMLDocument, testValue);
  assert_not_equals(window.HTMLDocument, testValue);

  heir.HTMLPreElement = testValue;
  assert_equals(heir.HTMLPreElement, testValue);
  assert_not_equals(window.HTMLPreElement, testValue);
}, "Prototype chain [[Set]] creates property on receiver");
</script>