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javascript instance accessor property

Set.prototype.size

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

Interactive exampleOpen the canonical MDN source to run this embedded demo.
const set = new Set();
const object = {};

set.add(42);
set.add("forty two");
set.add("forty two");
set.add(object);

console.log(set.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

const mySet = new Set();
mySet.add(1);
mySet.add(5);
mySet.add("some text");

console.log(mySet.size); // 3

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also