MDN may have intermittent access issues April 18 13:00 - April 19 01:00 UTC. See for all notifications.

Your Search Results


    This is an experimental technology, part of the ECMAScript 6 (Harmony) proposal.
    Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future version of browsers as the spec changes.


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




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

    Return value

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


    Example: 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 6 (ECMA-262)
    The definition of 'Map.prototype.has' in that specification.
    Release Candidate Initial definition.

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Basic support 38 13.0 (13.0) 11 25 7.1
    Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Basic support Not supported 38 13.0 (13.0) Not supported Not supported iOS 8

    See also

    Document Tags and Contributors

    Contributors to this page: realityking, fscholz
    Last updated by: realityking,