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weakMap.get

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

Syntax

wm.get(key);

Parameters

key: Required. The key of the element to return from the WeakMap object.

Return value

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

Examples

Using the `get` method

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

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

Specifications

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

Browser compatibility

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	36	Yes	6¹	11	23	8

Feature	Android webview	Chrome for Android	Edge mobile	Firefox for Android	Opera Android	iOS Safari	Samsung Internet
Basic support	36	36	Yes	6¹	23	8	?

1. 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.