[ES2024] Find Items from the end of the JavaScript Array using at, findLast and findLastIndex

Finding elements starting from the end of an array has gotten a lot easier with the introduction of the at, findLast, and findLastIndex methods!

With at you no longer need to remember to access the end of the array like array[array.length - 1] trick. You can just call .at[-1] to get the last element!

findLast and findLastIndex work the same as their find and findIndex counterparts. But, they work backwards from the end of the array. This is useful if you know what you're accessing is going to be closer to the end.

 

const arr = [1,2,3,4,5,6,7,8,9,10]

const item = arr.find(el => el >=9) // in the operation, it call the function 9 times before we got result

 

Since we know the item we want to find is on the right hand side of array, we can use findLastor findLastIndex

const arr = [1,2,3,4,5,6,7,8,9,10]

const item = arr.findLast(el => el >=9) // only call the function 1 time

 

.at()

const arr = [1,2,3,4,5,6,7,8,9,10]

const first = arr.at(0) // 1
const last = arr.at(-1) // 10