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


myMap.set(key, value);


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

Return value

The Map object.


Using set()

var 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');


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

Browser compatibility

Update compatibility data on GitHub
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
Partial support 11
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 Yesnodejs Full support Yes


Full support  
Full support
Partial support  
Partial support
See implementation notes.
See implementation notes.

See also

Document Tags and Contributors

Last updated by: alattalatta,