The set()
method adds a new element with a specified key
and value
to a WeakMap
object.
Syntax
wm.set(key, value);
Parameters
- key
- Required. The key of the element to add to the
WeakMap
object. - value
- Required. The value of the element to add to the
WeakMap
object.
Return value
The WeakMap
object.
Examples
Using the set
method
var wm = new WeakMap(); var obj = {}; // Add new elements to the WeakMap wm.set(obj, 'foo').set(window, 'bar'); // chainable // Update an element in the WeakMap wm.set(obj, 'baz');
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'WeakMap.prototype.set' in that specification. |
Standard | Initial definition. |
ECMAScript Latest Draft (ECMA-262) The definition of 'WeakMap.prototype.set' in that specification. |
Living Standard |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 36 | Yes | 61 | 112 | 23 | 8 |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
---|---|---|---|---|---|---|---|
Basic support | 36 | 36 | Yes | 61 | 11 | 23 | 8 |
1. Prior to Firefox 38, this method threw a TypeError
when the key parameter was not an object. This has been fixed in version 38 and later to return false
as per the ES2015 standard.
2. Returns 'undefined' instead of the 'Map' object.
Firefox-specific notes
- Prior to Firefox 33 (Firefox 33 / Thunderbird 33 / SeaMonkey 2.30),
WeakMap.prototype.set
returnedundefined
and was not chainable. This has been fixed (bug 1031632). The behavior can be found in Chrome/v8 as well (issue).