How to use apply() and map() Methods In Javascript

Method 1: Using JavaScript array() constructor

Method 3: Using JavaScript Array.from() Method

We will use apply() and map() methods to create an array with the given size. It will create an array without any value with a given size. But the values of the array will be undefined.

Example 1: In this example, we are using the apply() and map() method for creating an array.

Javascript

let arr = Array.apply(null, Array(5))
    .map(function () { });

console.log(arr.length);
console.log(arr);

Output:

5
[undefined, undefined, undefined, undefined, undefined]

Example 2: We will put the values of the indexes so it will give you an array of length 5 and its values will be the index number 0, 1, 2, 3, 4.

Javascript

let arr = Array.apply(null, Array(5))
    .map(function (y, i) { return i; });

console.log(arr.length);
console.log(arr)

Output:

5
[0, 1, 2, 3, 4]

Create an array of given size in JavaScript

Creating an array of a specific size can be achieved through various methods, each suited to different situations. In this article, we will explore several approaches to creating arrays of a desired size, accompanied by examples for each method.

Below are the following ways: