Ratatouille merge sort

merge-sort.js

let zucchiniSlices = [20, 11, 25, 3, 14, 5,...]
                      
const merge = (arr1, arr2) => {
  let sorted = [];
  while (arr1.length && arr2.length) {
    if (arr1[0] < arr2[0]) {
      sorted.push(arr1.shift());
    } else { 
      sorted.push(arr2.shift());
    }
  };
  return sorted.concat(arr1.slice().concat(arr2.slice()));
};

const mergeSortByBestSlices = veggieSlices => {
  if (veggieSlices.length <= 1) return veggieSlices;
  let mid = Math.floor(veggieSlices.length / 2),
      left = mergeSortByBestSlices(veggieSlices.slice(0, mid)),
      right = mergeSortByBestSlices(veggieSlices.slice(mid));

  return merge(left, right);
};

mergeSortByBestSlices(zucchiniSlices) // [1, 2, 3, 4, 5, 6,...]