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

js
keys()

Parameters

None.

Return value

Examples

Using keys()

js
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

desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
Deno
Node.js
keys

See also