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Set.prototype.has()

The has() method returns a boolean indicating whether an element with the specified value exists in a Set object 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

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
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25
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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/Set/has