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    Map.prototype.has()

    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.

    Summary

    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

    Example: Using the has method

    var myMap = new Map();
    myMap.set("bar", "foo");
    
    myMap.has("bar");  // returns true
    myMap.has("baz");  // returns false
    

    Specifications

    Specification Status Comment
    ECMAScript 6 (ECMA-262)
    The definition of 'Map.prototype.has' in that specification.
    Draft 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,