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

Specification
ECMAScript Language Specification
# sec-set.prototype.has

Browser compatibility

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See also