freeCodeCamp/guide/english/javascript/standard-objects/map/index.md

title
Map

Map

A map of [key, value] entries, where keys and values can be any value (both objects and primitive values).

Syntax

new Map([iterable])

Parameters

iterable An Array or other iterable object whose elements are key-value pairs.

Example

// basic usage
const myMap = new Map();
myMap.set('foo',1);
myMap.set('bar',2);
myMap.set('baz',3);

myMap.get('foo');   // returns 1
myMap.get('baz');   // returns 3
myMap.get('hihi');  // return undefined

myMap.size();   // 3