How to use Spread Operator In Javascript

We can also use Spread Operator to create an array containing 1…N numbers. We use Array() constructor to create a new array of length N, and then use keys() method to get an iterator over the indices of the array. Then spread the iterator into an array using the spread operator (…) and map each element of the resulting array to its corresponding index value plus 1.

Example: In this example, we are using Spread Operator.

Javascript
function createArray(N) {
    return [...Array(N).keys()].map(i => i + 1);
}

let N = 12;
let arr = createArray(N);
console.log(arr);

Output
[
   1,  2, 3, 4,  5,
   6,  7, 8, 9, 10,
  11, 12
]

How to create an array containing 1…N numbers in JavaScript ?

In this article, we will see how to create an array containing 1. . . N numbers using JavaScript. We can create an array by using different methods.

There are some methods to create an array containing 1…N numbers, which are given below:

Table of Content

  • Using for Loop
  • Using Spread Operator
  • Using from() Method
  • Using third-party library
  • Using a Generator Function

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Using for Loop

We can use a for loop to create an array containing numbers from 1 to N in JavaScript. The for loop iterates from 1 to N and pushes each number to an array....

Using Spread Operator

We can also use Spread Operator to create an array containing 1…N numbers. We use Array() constructor to create a new array of length N, and then use keys() method to get an iterator over the indices of the array. Then spread the iterator into an array using the spread operator (…) and map each element of the resulting array to its corresponding index value plus 1....

Using from() Method

We can also use the Array.from() method to create an array containing numbers from 1 to N....

Using third-party library

The _.range() method is used to create an array of numbers progressing from the given start value up to, but not including the end value....

Using a Generator Function

A generator function generateNumbers(N) yields numbers from 1 to N. Spread the generator’s values into an array using `[…generateNumbers(N)]`, creating an array of numbers from 1 to N efficiently....