Detailed explanation of steps to implement PHP array recursive sorting

/**
 * 递归根据特定key对数组排序
 * @param $data
 * @param string $orderKey
 * @param string $sonKey
 * @param int $orderBy
 * @return mixed
 */
function recursion_orderby($data, $orderKey = 'order', $sonKey = 'children', $orderBy = SORT_ASC)
{
  $func = function ($value) use ($sonKey, $orderKey, $orderBy) {
    if (isset($value[$sonKey]) && is_array($value[$sonKey])) {
      $value[$sonKey] = recursion_orderby($value[$sonKey], $orderKey, $sonKey, $orderBy);
    }
    return $value;
  };
  return array_orderby(array_map($func, $data), $orderKey, $orderBy);
}
$a = [
  [
    'order' => 0,
  ],
  [
    'order' => -1,
    'children' => [
      [
        'order' => 0,
      ],
      [
        'order' => -2,
        'children' => [
          ['order' => 0],
          ['order' => -1],
          ['order' => 1],
        ],
      ],
    ],
  ],
  [
    'order' => 2,
  ],
];
var_dump(recursion_orderby($a));
/**
 * 输出：
array(3) {
 [0] =>
 array(2) {
  'order' =>
  int(-1)
  'children' =>
  array(2) {
   [0] =>
   array(2) {
    'order' =>
    int(-2)
    'children' =>
    array(3) {
     [0] =>
     array(1) {
      'order' =>
      int(-1)
     }
     [1] =>
     array(1) {
      'order' =>
      int(0)
     }
     [2] =>
     array(1) {
      'order' =>
      int(1)
     }
    }
   }
   [1] =>
   array(1) {
    'order' =>
    int(0)
   }
  }
 }
 [1] =>
 array(1) {
  'order' =>
  int(0)
 }
 [2] =>
 array(1) {
  'order' =>
  int(2)
 }
}
*/