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WeakMap.prototype

The WeakMap.prototype property represents the prototype for the WeakMap constructor.

Property attributes of WeakMap.prototype
Writable no
Enumerable no
Configurable no

Description

WeakMap instances inherit from WeakMap.prototype. You can use the constructor's prototype object to add properties or methods to all WeakMap instances.

WeakMap.prototype is itself just an ordinary object:

Object.prototype.toString.call(WeakMap.prototype); // "[object Object]"

Properties

WeakMap.prototype.constructor
Returns the function that created an instance's prototype. This is the WeakMap function by default.

Methods

WeakMap.prototype.delete(key)
Removes any value associated to the key. WeakMap.prototype.has(key) will return false afterwards.
WeakMap.prototype.get(key)
Returns the value associated to the key, or undefined if there is none.
WeakMap.prototype.has(key)
Returns a Boolean asserting whether a value has been associated to the key in the WeakMap object or not.
WeakMap.prototype.set(key, value)
Sets the value for the key in the WeakMap object. Returns the WeakMap object.
WeakMap.prototype.clear()
Removes all key/value pairs from the WeakMap object. Note that it is possible to implement a WeakMap-like object that has a .clear() method by encapsulating a WeakMap object that hasn't it (see example on page WeakMap)

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 36 Yes 6 11 23 8
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 37 36 Yes 6 23 8 Yes
Server
Node.js
Basic support 0.12
0.12
0.10
Disabled
Disabled From version 0.10: this feature is behind the --harmony runtime flag.

See also

© 2005–2018 Mozilla Developer Network and individual 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/prototype