JavaScript Map set() Method (original) (raw)

Last Updated : 15 Jul, 2024

The JavaScript **map.set() method is used to add **key-value pairs to a Map object. It can also be used to update the value of an existing key. Each value must have a unique key so that they get mapped correctly.

**Syntax:

GFGmap.set(key, value);

**Parameters:

This method accepts two parameters as mentioned above and described below:

• **Key: This is the key of the item that has to be added or updated in the Map.
• **Value: This is the value of the item that has to be added or updated in the Map.

**Example 1:

JavaScript `

let GFGMap = new Map();

// Adding a key value pair GFGMap.set(1, "India");

// Getting the value by key console.log(GFGMap.get(1));

// Updating the existing value GFGMap.set(1, "England");

// Getting the value back console.log(GFGMap.get(1));

`

**Output:

India
England

**Example 2: Using set() with chaining

JavaScript `

let myMap = new Map();

// Adding key value pair with chaining myMap.set(1, "Rohan").set(2, "Sohan").set(3, "Trojan");

// Getting the values back console.log(myMap.get(1)); console.log(myMap.get(2)); console.log(myMap.get(3));

`

**Output:

Rohan
Sohan
Trojan

**Supported Browsers:

• Chrome 38
• Edge 12
• Firefox 13
• Opera 25
• Safari 8