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