JavaScript Map set() Method

The 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.

The examples below illustrate the set() method:

Example 1:

Javascript

<script>
  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));
</script>

Output :

India
England

Example 2: Using set() with chaining

Javascript

<script>
  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));
</script>

Output :

Rohan
Sohan
Trojan