JavaScript · Collections, storage and utilities

Map object

A keyed collection that accepts any key type and remembers insertion order.

javascriptRunnable example javascript course

Syntax

new Map([[key, value]])

Example

Try it

const scores = new Map([["html", 90]]);
scores.set("css", 85);
console.log(scores.get("html"), scores.size);

Reference pages are the quick answer. The course explains the why, shows the full example and ends with a challenge.