weakMap.set

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 2017 Draft (ECMA-262) The definition of 'WeakMap.prototype.set' in that specification.	Draft

Browser compatibility

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

• WeakMap
• WeakMap.prototype.get()
• WeakMap.prototype.has()