Set.prototype.has()

The has() method of Set instances returns a boolean indicating whether an element with the specified value exists in this set or not.

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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

Docs

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