Discussion on: Sorting Algorithms in Javascript Part 2

Wouldn't this be simpler?

const swap = (arr, a, b) => { [arr[a], arr[b]] = [arr[b], arr[a]] }

Better still, a version that doesn't mutate the original array:

const swap = (arr, a, b) => {
   let ret = [...arr];
   [ret[a], ret[b]] = [ret[b], ret[a]];
   return ret;
}

Also, your counting sort function both mutates and returns the original array whilst your bucket sort array returns a new array, leaving the original untouched (better). This code is somewhat confused - better to stick with either mutating variables or not, don't mix the two.