Map.prototype.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

DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
setChrome Full support 38Edge Full support 12Firefox Full support 13IE Partial support 11
Notes
Partial support 11
Notes
Notes Returns 'undefined' instead of the 'Map' object.
Opera Full support 25Safari Full support 8WebView Android Full support 38Chrome Android Full support 38Firefox Android Full support 14Opera Android Full support 25Safari iOS Full support 8Samsung Internet Android Full support 3.0nodejs 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.

See also