Web/JavaScript/Reference/Global objects/Map/set

The set() method adds or updates an element with a specified key and a value to a Map object.

Syntax

myMap.set(key, value)

Parameters

key: The key of the element to add to the Map object.
value: The value of the element to add to the Map object.

Return value

The Map object.

Examples

Using set()

let myMap = new Map()

// Add new elements to the map
myMap.set('bar', 'foo')
myMap.set(1, 'foobar')

// Update an element in the map
myMap.set('bar', 'baz')

Using the set() with chaining

Since the set() method returns back the same Map object, you can chain the method call like below:

// Add new elements to the map with chaining. 
myMap.set('bar', 'foo')
     .set(1, 'foobar')
     .set(2, 'baz');

Specifications

Specification

ECMAScript (ECMA-262)The definition of 'Map.prototype.set' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`set`	Chrome Full support 38	Edge Full support 12	Firefox Full support 13	IE Partial support 11 Notes' Partial support 11 Notes' Notes' Returns 'undefined' instead of the 'Map' object.	Opera Full support 25	Safari Full support 8	WebView Android Full support 38	Chrome Android Full support 38	Firefox Android Full support 14	Opera Android Full support 25	Safari iOS Full support 8	Samsung Internet Android Full support 3.0	nodejs Full support 0.12 Full support 0.12 Full support 0.10 Disabled' Disabled' From version 0.10: this feature is behind the `--harmony` runtime flag.

Legend

Full support: Full support
Partial support: Partial support
See implementation notes.': See implementation notes.
User must explicitly enable this feature.': User must explicitly enable this feature.