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




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.


Using the get method

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.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support36 Yes6111238
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support3636 Yes61238 Yes

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.

2. From version 0.10: this feature is behind the --harmony runtime flag.

See also

Document Tags and Contributors

Contributors to this page: wbamberg, fscholz, jameshkramer, nmve, kdex, eduardoboucas, realityking
Last updated by: wbamberg,