Merge sort JS implementation

merge-sort.js

function mergeSort(nums){
  if (nums.length === 1) return nums;
  
  const half = Math.floor(nums.length / 2);
  
  const left = mergeSort(nums.slice(0, half));
  const right = mergeSort(nums.slice(half));
  
  return merge(left, right);
}

function merge(left, right){
  let result = [];
  let l = 0, r = 0;
  
  while (l < left.length && r < right.length){
    if (left[l] < right[r]){
      result.push(left[l]);
      l++;
    } else {
      result.push(right[r]);
      r++;
    }
  }
  
  if (l < left.length){
    result = result.concat(left.slice(l));
  } else if (r < right.length) {
    result = result.concat(right.slice(r));
  }
  
  return result;
}

const nums = Array(10).fill(100).map(n => parseInt(n * Math.random()));

console.log(mergeSort(nums));