按嵌套键对数组排序，同时保持现有排序不变

function nestedSort(arr, key) {
  if (arr.length <= 1) {
    return arr;
  }

  const pivot = arr[0];
  const less = [];
  const equal = [];
  const greater = [];

  for (const obj of arr) {
    const compare = compareNestedKeys(obj, pivot, key);
    if (compare < 0) {
      less.push(obj);
    } else if (compare === 0) {
      equal.push(obj);
    } else {
      greater.push(obj);
    }
  }

  return [...nestedSort(less, key), ...equal, ...nestedSort(greater, key)];
}

function compareNestedKeys(obj1, obj2, key) {
  const value1 = getNestedValue(obj1, key);
  const value2 = getNestedValue(obj2, key);

  if (value1 < value2) {
    return -1;
  } else if (value1 > value2) {
    return 1;
  } else {
    return arr.indexOf(obj1) - arr.indexOf(obj2);
  }
}

function getNestedValue(obj, key) {
  const keys = key.split('.');
  let value = obj;

  for (const k of keys) {
    value = value[k];
  }

  return value;
}

// 示例数据
const arr = [
  { name: 'John', age: 25 },
  { name: 'Alice', age: 30 },
  { name: 'Bob', age: 20 },
  { name: 'Alice', age: 35 },
  { name: 'John', age: 40 }
];

const sortedArr = nestedSort(arr, 'name');
console.log(sortedArr);