Laravel实现分类无限递归

/**
 * getTree无限递归函数
 * @param $data
 * @param $field_id
 * @param $field_pid
 * @param int $pid
 * @return array
 * @fillable 变量，保存子集数据
 */
public function getTree($data, $field_id, $field_pid, $pid = 0) {
    $arr = array();
    foreach ($data as $k=>$v) {
        if ($v->$field_pid == $pid) {
            $arr[$k] = $v;
            $arr[$k]['fillable'] = self::getTree($data, $field_id, $field_pid, $v->$field_id );
        }
    }
    return $arr;
}