JavaScript Map() Constructor
Last Updated :
24 May, 2023
The Map() constructor is used to create Map objects in JavaScript. The map is a data structure that stores elements as a key, value pair.
Syntax:
new Map()
new Map(iterable)
Parameters:
- iterable: An iterable object used for iterating through elements, stored as a key, value pair.
Return value: A new Map object returns after the initialization of the map constructor.
Example 1:
Javascript
let map1 = new Map([
[1, 10], [2, 20],
[3, 30], [4, 40]
]);
console.log( "Map1: " );
console.log(map1);
|
Output:
Map1:
Map(4) { 1 => 10, 2 => 20, 3 => 30, 4 => 40 }
Example 2:
Javascript
let map2 = new Map([
[ "firstname" , "Ram" ],
[ "lastname" , "Prasad" ],
[ "website" , "geeksforgeeks" ]
]);
console.log( "Map2: " );
console.log(map2);
|
Output:
Map2:
Map(3) {
'firstname' => 'Ram',
'lastname' => 'Prasad',
'website' => 'geeksforgeeks'
}
Example 3:
Javascript
let map3 = new Map([
[ "whole numbers" , [1, 2, 3, 4]],
[ "Decimal numbers" , [1.1, 1.2, 1.3, 1.4]],
[ "negative numbers" , [-1, -2, -3, -4]]
]);
console.log( "Map3: " );
console.log(map3);
|
Output:
Map3:
Map(3) {
'whole numbers' => [ 1, 2, 3, 4],
'Decimal numbers' => [ 1.1, 1.2, 1.3, 1.4],
'negative numbers' => [ -1, -2, -3, -4]
}
Supported Browsers:
- Chrome 38 and above
- Edge 12 and above
- Firefox 13 and above
- Internet Explorer 11 and above
- Opera 25 and above
- Safari 8 and above
We have a complete list of Javascript Map methods, to check those please go through this JavaScript MapComplete Reference article.
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