JavaScript Map has() method

The has method of the JavaScript Map object determines if a specific key exists within the Map. It yields a true value if the key in question is found, and false if it is not present.

Syntax

The syntax for the has method is illustrated as follows:

mapObj.has(key)

Parameter

key - It represents the key to be searched.

Return

A Boolean value.

JavaScript Map has method example

In this section, we will explore the has method by examining a variety of examples.

Example 1

Let us examine an example to ascertain if the map object includes the given key.

<script>

var map=new Map();

map.set(1,"jQuery");

map.set(2,"AngularJS");

map.set(3,"Bootstrap");

document.writeln(map.has(2)); 

</script>

Output:

Example 2

Let us examine an additional example to ascertain if the map object holds the given key.

<script>

var map=new Map();

map.set(1,"jQuery");

map.set(2,"AngularJS");

map.set(3,"Bootstrap");

document.writeln(map.has(5)); 

</script>

Output:

Example 3

Let's examine the outcome when the has method is invoked without providing a specific key.

<script>

var map=new Map();

map.set(1,"jQuery");

map.set(2,"AngularJS");

map.set(3,"Bootstrap");

document.writeln(map.has()+"<br>");

document.writeln(map.has("jQuery")); 

</script>

Output:

false

false