菜单实现无限极分类树

public function index()
    {
        $data=Category::select()->order('sort','desc')->toArray();
        $items = [];
        foreach ($data as $v){
            $items[$v['id']] = $v;
        }
        $tree = array(); //格式化好的树
        foreach ($items as $item)
            if (isset($items[$item['pid']]))
                $items[$item['pid']]['son'][] = &$items[$item['id']];
            else
                $tree[] = &$items[$item['id']];
        return $this->success($tree);

    }
/**
     * tree 子菜单
     * @param array $data 数据
     * @param string $childrenname 子数据名
     * @param string $keyName 数据key名
     * @param string $pidName 数据上级key名
     * @return array
     */
    function get_tree_children($data,$childrenname = 'children',$keyName = 'id',$pidName = 'pid')
    {
        $list = array();
        foreach ($data as $value) {
            $list[$value[$keyName]] = $value;
        }
        static $tree = array(); //格式化好的树
        foreach ($list as $item) {
            if (isset($list[$item[$pidName]])) {
                $list[$item[$pidName]][$childrenname][] = &$list[$item[$keyName]];
            } else {
                $tree[] = &$list[$item[$keyName]];
            }
        }
        return $tree;
    }