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 Mapobject.
Return value
- Boolean
- Returns trueif an element with the specified key exists in theMapobject; otherwisefalse.
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 Latest Draft (ECMA-262) The definition of 'Map.prototype.has' in that specification. | Draft | 
Browser compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari | 
|---|---|---|---|---|---|---|
| Basic support | 38 | (Yes) | 13.0 (13.0) | 11 | 25 | 7.1 | 
| Feature | Android | Chrome for Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | 
|---|---|---|---|---|---|---|---|
| Basic support | No support | 38 | (Yes) | 13.0 (13.0) | No support | No support | 8 |