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




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.


Using the has method

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

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


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Map.prototype.has' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Map.prototype.has' in that specification.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
hasChrome Full support 38Edge Full support 12Firefox Full support 13IE Full support 11Opera Full support 25Safari Full support 8WebView Android Full support 38Chrome Android Full support 38Edge Mobile Full support 12Firefox Android Full support 14Opera Android Full support 25Safari iOS Full support 8Samsung Internet Android Full support Yesnodejs Full support Yes


Full support  
Full support

See also

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