Map.prototype.keys()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The keys() method of Map instances returns a new map iterator object that contains the keys for each element in this map in insertion order.

Try it

Syntax

keys()

Parameters

None.

Return value

A new iterable iterator object.

Examples

Using keys()

const myMap = new Map();
myMap.set("0", "foo");
myMap.set(1, "bar");
myMap.set({}, "baz");

const mapIter = myMap.keys();

console.log(mapIter.next().value); // "0"
console.log(mapIter.next().value); // 1
console.log(mapIter.next().value); // {}

Specifications

Specification
ECMAScript Language Specification # sec-map.prototype.keys

Browser compatibility

	Desktop					Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`keys`	38	12	20	25	8	38	20	25	8	3.0	38	1.0	0.12.0