WeakMap.prototype.get()
The get() method returns a specified element from a WeakMap object.
Syntax
JavaScript
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wm.get(key);
Parameters
- key
- Required. The key of the element to return from the
WeakMapobject.
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
JavaScript
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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 2017 Draft (ECMA-262) The definition of 'WeakMap.prototype.get' in that specification. |
Draft |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | 36 | 6.0 (6.0) | 11 | 23 | 7.1 |
| Feature | Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|
| Basic support | No support | 6.0 (6.0) | No support | No support | 8 |
Firefox-specific notes
- Prior to SpiderMonkey 38 (Firefox 38 / Thunderbird 38 / SeaMonkey 2.35), this method threw a
TypeErrorwhen the key parameter was not an object. However, the latest ES6 standard specifies to returnundefinedinstead. Furthermore,WeakMap.prototype.getaccepted 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 (bug 1127827).
See also
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/javascript/reference/global_objects/weakmap/get