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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

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
get 36 12 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 Firefox for Android Opera for Android Safari on iOS Samsung Internet
get 37 36 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.
24 8 3.0
Server
Node.js
get 0.12
0.12
0.10
Disabled
Disabled From version 0.10: this feature is behind the --harmony runtime flag.

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/get