Code Snippets - Pre-populate an array in JavaScript

This is the second post I write about code snippets I find useful (you can check the first one here). And today's code snippet is how to pre-populate an array in JavaScript.

The for loop is probably one of the first choices that comes to mind when dealing with arrays or collections. But instead, I prefer to create an array with Array.from.

If you've never heard of Array.from before, it accepts and array-like or an iteratable object as its first argument so we can map into it. Once the array is created, map gives us each element in the newly created array so we can populate it with, for example, the index of each element.

function createArray(size: number) {
  return Array.from({ length: size }).map((_, index) => index + 1)
}

or using the Array constructor:

function createArray(size: number) {
  return Array.from(Array(size)).map((_, index) => index + 1)
}

I hope that's helpful and interesting to you. 👋🏼