refactor(core): use has instead of get to test for existence in ExecE…

…nv (#7763)

refactor(core): use has instead of get to test for existence

packages/docusaurus/src/client/exports/ExecutionEnvironment.ts

@@ -5,23 +5,22 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-const canUseDOM = !!(
+const canUseDOM =
  typeof window !== 'undefined' &&
- window.document &&
- window.document.createElement
-);
+ 'document' in window &&
+ 'createElement' in window.document;
 
 const ExecutionEnvironment = {
  canUseDOM,
 
+ // window.attachEvent is IE-specific; it's very likely Docusaurus won't work
+ // on IE anyway.
  canUseEventListeners:
- // @ts-expect-error: window.attachEvent is IE specific.
- // See https://github.com/Microsoft/TypeScript/issues/3953#issuecomment-123396830
- canUseDOM && !!(window.addEventListener || window.attachEvent),
+ canUseDOM && ('addEventListener' in window || 'attachEvent' in window),
 
  canUseIntersectionObserver: canUseDOM && 'IntersectionObserver' in window,
 
- canUseViewport: canUseDOM && !!window.screen,
+ canUseViewport: canUseDOM && 'screen' in window,
 };
 
 export default ExecutionEnvironment;