How can you sort an array without mutating the original array?

Question

Let\'s suppose I wanted a sort function that returns a sorted copy of the inputted array. I naively tried this

function sort(arr) {
  return arr.sort();
}
         


        

Answer 1

You need to copy the array before you sort it. One way with es6:

const sorted = [...arr].sort();

the spread-syntax as array literal (copied from mdn):

var arr = [1, 2, 3];
var arr2 = [...arr]; // like arr.slice()

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator