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Set.prototype.size

The size accessor property of Set instances returns the number of (unique) elements in this set.

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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 Language Specification # sec-get-set.prototype.size

Browser compatibility

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`size`	38	12	19 From Firefox 13 to Firefox 18, the `size` property was implemented as a `Set.prototype.size()` method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.	25	8	38	19 From Firefox 13 to Firefox 18, the `size` property was implemented as a `Set.prototype.size()` method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.	25	8	3.0	38	1.0	0.12.0

See also

Set

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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/size