Function mergeSort

javascript/0912-sort-an-array.js:12–19

(left, right, nums)

};

const mergeSort = (left, right, nums) => {
    if (left === right) return nums;

    const mid = Math.floor((left + right) / 2);
    mergeSort(left, mid, nums);
    mergeSort(mid + 1, right, nums);
    return merge(left, right, mid, nums);
};

const merge = (left, right, mid, nums) => {
    const arr1 = nums.slice(left, mid + 1);