如何访问我所指向的数组中的所有元素，并在mergeSort函数调用期间更改它们？

function mergeSort(arr) {
  if (arr.length === 1) {
    return arr;
  }

  const mid = Math.floor(arr.length / 2);
  const left = arr.slice(0, mid);
  const right = arr.slice(mid);

  return merge(mergeSort(left), mergeSort(right));
}

function merge(left, right) {
  let result = [];

  while (left.length && right.length) {
    if (left[0] <= right[0]) {
      result.push(left.shift());
    } else {
      result.push(right.shift());
    }
  }

  return result.concat(left).concat(right);
}

// 使用示例
const arr = [4, 2, 1, 3];
const sortedArr = mergeSort(arr);
console.log(sortedArr);