How to add an item at the beginning of an array in JavaScript
Say you want to add an item at the beginning of an array.
To perform this operation you will use the splice()
method of an array.
splice()
takes 3 or more arguments. The first is the start index: the place where we’ll start making the changes. The second is the delete count parameter. We’re adding to the array, so the delete count is 0 in all our examples. After this, you can add one or many items to add to the array.
To add at the first position, use 0
as the first argument:
const colors = ['yellow', 'red']
colors.splice(0, 0, 'blue')
//colors === ['blue', 'yellow', 'red']
→ I wrote 17 books to help you become a better developer, download them all at $0 cost by joining my newsletter
→ JOIN MY CODING BOOTCAMP, an amazing cohort course that will be a huge step up in your coding career - covering React, Next.js - next edition February 2025