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

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Map.prototype.has' in that specification.	Standard	Initial definition.
ECMAScript 2017 Draft (ECMA-262) The definition of 'Map.prototype.has' in that specification.	Draft

Browser compatibility

See also

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