Web/JavaScript/Reference/Global objects/Map/has

The has() method returns a boolean indicating whether an element with the specified key exists or not.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

myMap.has(key)

Parameters

key

The key of the element to test for presence in the Map object.

Return value

true if an element with the specified key exists in the Map object; otherwise false.

Examples

Using has()

let myMap = new Map()
myMap.set('bar', "foo")

myMap.has('bar')   // returns true
myMap.has('baz')   // returns false

Specifications

Specification

ECMAScript (ECMA-262)The definition of 'Map.prototype.has' in that specification.

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.

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
has	Chrome Full support 38	Edge Full support 12	Firefox Full support 13	IE Full support 11	Opera Full support 25	Safari Full support 8	WebView Android Full support 38	Chrome Android Full support 38	Firefox Android Full support 14	Opera Android Full support 25	Safari iOS Full support 8	Samsung Internet Android Full support 3.0	nodejs Full support 0.12 Full support 0.12 Full support 0.10 Disabled' Disabled' From version 0.10: this feature is behind the --harmony runtime flag.

Legend

Full support  

Full support

User must explicitly enable this feature.'

User must explicitly enable this feature.

See also

• Map
• Map.prototype.set()
• Map.prototype.get()

Map.prototype.has() by Mozilla Contributors is licensed under CC-BY-SA 2.5.