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map.has

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

Syntax

myMap.has(key);

Parameters

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

Return value

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

Examples

Using the has method

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

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

Specifications

Browser compatibility

Feature Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 38 12 13 11 25 8
Feature Android webview Chrome for Android Edge mobile Firefox for Android Opera Android iOS Safari Samsung Internet
Basic support 38 38 12 14 25 8 ?

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/Map/has