Set.prototype.size
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The size
accessor property of Set
instances returns the number of (unique) elements in this set.
Try it
const set1 = new Set();
const object1 = {};
set1.add(42);
set1.add("forty two");
set1.add("forty two");
set1.add(object1);
console.log(set1.size);
// Expected output: 3
Description
The value of size
is an integer representing how many entries the Set
object has. A set accessor function for size
is undefined
; you cannot change this property.
Examples
Using size
js
const mySet = new Set();
mySet.add(1);
mySet.add(5);
mySet.add("some text");
console.log(mySet.size); // 3
Specifications
Specification |
---|
ECMAScript® 2025 Language Specification # sec-get-set.prototype.size |