Map.prototype.has() - JavaScript | MDN (original) (raw)

Baseline

Widely available

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

const map1 = new Map();
map1.set("bar", "foo");

console.log(map1.has("bar"));
// Expected output: true

console.log(map1.has("baz"));
// Expected output: false

Syntax

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

Browser compatibility

See also