Map.prototype.has()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The has() method of Map instances returns a boolean indicating whether an element with the specified key exists in this map or not.

Try it

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 Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
has 38 12 13 25 8 38 14 25 8 3.0 38 1.0 0.12.0

See also

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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/has