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()")}} 

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

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()")}}