Set.prototype.add()

The add() method of {{jsxref("Set")}} instances inserts the specified value into this set, if it is not already present.

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

```js interactive-example const set = new Set();

set.add(42); set.add(42); set.add(13);

for (const item of set) { console.log(item); // Expected output: 42 // Expected output: 13 }

## Syntax

```js-nolint
add(value)

Parameters#

• value
• : The value to add to the Set object. Objects are compared by reference, not by value.

Return value#

The Set object.

Examples#

Using add()#

const mySet = new Set();

mySet.add(1);
mySet.add(5).add("some text"); // chainable

console.log(mySet);
// Set [1, 5, "some text"]

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

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