javascript instance accessor property
Map.prototype.size
The size accessor property of Map instances returns the number of elements in this map.
Interactive exampleOpen the canonical MDN source to run this embedded demo.
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
const myMap = new Map();
myMap.set("a", "alpha");
myMap.set("b", "beta");
myMap.set("g", "gamma");
console.log(myMap.size); // 3
Specifications
SpecificationsStandards references are available on the canonical MDN page.
Browser compatibility
Browser compatibilityCompatibility data is available on the canonical MDN page.