WeakMap.prototype.set()

The set() method adds a new element with a specified key and value to a WeakMap object.

Syntax

JavaScript
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

JavaScript
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 2017 Draft (ECMA-262)
The definition of 'WeakMap.prototype.set' 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 Firefox 33 (Firefox 33 / Thunderbird 33 / SeaMonkey 2.30), WeakMap.prototype.set returned undefined and was not chainable. This has been fixed (bug 1031632). The behavior can be found in Chrome/v8 as well (issue).

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/set

ECMAScript6 JavaScript Method Prototype WeakMap