Map.prototype.keys()

by 3 contributors:

This is a new technology, part of the ECMAScript 2015 (ES6) standard .
This technology's specification has been finalized, but check the compatibility table for usage and implementation status in various browsers.

The keys() method returns a new Iterator object that contains the keys for each element in the Map object in insertion order.

Syntax

myMap.keys()

Examples

Using keys()

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

var mapIter = myMap.keys();

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

Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Map.prototype.keys' in that specification.
Standard Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 38 20 (20) Not supported 25 7.1
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support Not supported 38 20.0 (20) Not supported Not supported 8

See also

Document Tags and Contributors

Contributors to this page: fscholz, arai, realityking
Last updated by: fscholz,