Set.prototype.has()

The has() method of {{jsxref("Set")}} instances returns a boolean indicating whether the specified value exists in this Set or not.

{{InteractiveExample("JavaScript Demo: Set.prototype.has()")}}

```js interactive-example const set = new Set([1, 2, 3, 4, 5]);

console.log(set.has(1)); // Expected output: true

console.log(set.has(5)); // Expected output: true

console.log(set.has(6)); // Expected output: false

## Syntax

```js-nolint
has(value)

Parameters#

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

Return value#

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

Examples#

Using has()#

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

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

const set = new Set();
const obj = { key1: 1 };
set.add(obj);

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

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Set")}}
• {{jsxref("Set.prototype.add()")}}
• {{jsxref("Set.prototype.delete()")}}