Set.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 Set instances returns a boolean indicating whether an element with the specified value exists in this set or not.

Try it

Syntax

has(value)

Parameters

value: The value to test for presence in the Set object.

Return value

Returns true if an element with the specified value exists in the Set object; otherwise false.

Examples

Using the has() method

const mySet = new Set();
mySet.add("foo");

console.log(mySet.has("foo")); // true
console.log(mySet.has("bar")); // false

const set1 = new Set();
const obj1 = { key1: 1 };
set1.add(obj1);

console.log(set1.has(obj1)); // true
console.log(set1.has({ key1: 1 })); // false, because they are different object references
console.log(set1.add({ key1: 1 })); // now set1 contains 2 entries

Specifications

Specification
ECMAScript Language Specification # sec-set.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