How to useArray.from() with a Mapping Function in Javascript

Using Array.from() with a mapping function, the code creates a two-dimensional array by specifying the number of rows and columns. Each cell is initialized using the mapping function to fill the array with a specified initial value.

Example

JavaScript
let rows = 3;
let cols = 4;
let initialValue = undefined;

let arr = Array.from({ length: rows }, () => Array(cols).fill(initialValue));

// Example usage
console.log(arr); 

Output
[
  [ undefined, undefined, undefined, undefined ],
  [ undefined, undefined, undefined, undefined ],
  [ undefined, undefined, undefined, undefined ]
]




How to Declare Two Dimensional Empty Array in JavaScript ?

In this article, we are going to learn about Declare two-dimensional empty array by using JavaScript. A two-dimensional array is also known as a 2D array. It is a data structure in JavaScript that can hold values in rows and columns form. It is an array of arrays. Each element in a 2D array is accessible using two indices, and it is represented as an array[rowIndex][columnIndex].

There are several methods that can be used to add elements to Declare an empty two-dimensional array in JavaScript, which are listed below:

Table of Content

  • Using a Loop
  • Using the Array() Constructor

We will explore all the above methods along with their basic implementation with the help of examples.

Similar Reads

Approach 1: Using a Loop

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Approach 2: Using the Array() Constructor

In this approach, we are using nested loops to iterate over the rows and columns of the 2D array and initialize each element to a specific value as null or undefined....

Approach 3: Using Array.from() with a Mapping Function

JavaScript provides the Array() constructor, which allows us to create an array of a specific length. We can use this constructor to create a 2D array by initializing each element as an empty array....

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