JavaScript Map has() Method

The Map.has() method in Javascript is used to check whether an element with a specified key exists in a map or not. It returns a boolean value indicating the presence or absence of an element with a specified key in a map. The Map.has() method takes the key of the element to be searched as an argument and returns a boolean value. It returns true if the element exists in the map else it returns false if the element doesn’t exist.

Syntax:

mapObj.has(key)

Parameters Used:

key: It is the key of the element of the map which has to be searched.

Return Value: The Map.has() method returns a boolean value. It returns true if the element exists in the map else it returns false if the element doesn’t exist.

Examples of the above function are provided below.

Example 1: In this example, a map object “myMap” has been created with a single [key, value] pair, and the Map.has() method is used to check whether an element with the key ‘0’ exists in the map or not.

javascript

// creating a map object
let myMap = new Map();
  
// Adding [key, value] pair to the map
myMap.set(0, 'geeksforgeeks');
  
// displaying whether an element with 
// the key '0' exists in the map or not
// using Map.has() method
console.log(myMap.has(0));

Output:

true

Example 2: In this example, a map object “myMap” has been created with three [key, value] pairs, and the Map.has() method is used to check whether an element with the key ‘0’ and ‘3’ exists in the map or not.

javascript

// creating a map object
let myMap = new Map();
  
// Adding [key, value] pair to the map
myMap.set(0, 'geeksforgeeks');
myMap.set(1, 'is an online portal');
myMap.set(2, 'for geeks');
  
// displaying whether an element with the
// key '0' and '3' exists in
// the map or not using Map.has() method
console.log(myMap.has(0));
console.log(myMap.has(3));