Map.prototype.size
Baseline
Widely available
This feature is well established and works across many devices and browser versions. Itās been available across browsers since āØJuly 2015ā©.
The size accessor property of Map instances returns the number of elements in this map.
Try it
const map = new Map();
map.set("a", "alpha");
map.set("b", "beta");
map.set("g", "gamma");
console.log(map.size);
// Expected output: 3
Description
The value of size is an integer representing how many entries the Map object
has. A set accessor function for size is undefined; you can not change this
property.
Examples
Using size
js
const myMap = new Map();
myMap.set("a", "alpha");
myMap.set("b", "beta");
myMap.set("g", "gamma");
console.log(myMap.size); // 3
Specifications
| Specification |
|---|
| ECMAScriptĀ® 2026 LanguageĀ Specification # sec-get-map.prototype.size |