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weakMap.get

The get() method returns a specified element from a WeakMap object.

wm.get(key);

The element associated with the specified key in the WeakMap object. If the key can't be found, undefined is returned.

var wm = new WeakMap();
wm.set(window, 'foo');

wm.get(window); // Returns "foo".
wm.get('baz');  // Returns undefined.

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'WeakMap.prototype.get' in that specification.	Standard	Initial definition.
ECMAScript Latest Draft (ECMA-262) The definition of 'WeakMap.prototype.get' in that specification.	Draft

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	36	Yes	6 6 Prior to Firefox 38, this method threw a `TypeError` when the key parameter was not an object. However, the ES2015 specification specifies to return `undefined` instead. Furthermore, `WeakMap.prototype.get` accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher.	11	23	8

	Mobile
	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support	37	36	Yes	6 6 Prior to Firefox 38, this method threw a `TypeError` when the key parameter was not an object. However, the ES2015 specification specifies to return `undefined` instead. Furthermore, `WeakMap.prototype.get` accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher.	23	8	Yes

	Server
	Node.js
Basic support	0.12 0.12 0.10 Disabled Disabled From version 0.10: this feature is behind the `--harmony` runtime flag.