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Map.prototype.has()

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

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Syntax

has(key)

Parameters

key

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.

Examples

Using has()

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

console.log(myMap.has("bar")); // true
console.log(myMap.has("baz")); // false

Specifications

Specification
ECMAScript Language Specification
# sec-map.prototype.has

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet Deno Node.js
has
38
12
13
11
25
8
38
38
14
25
8
3.0
1.0
0.12.0
0.10.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/has