php 无限极分类 引用

public function index(){
    $catList = [
        '1' => ['id' => 1, 'name' => '颜色', 'parent_id' => 0],
        '2' => ['id' => 2, 'name' => '规格', 'parent_id' => 0],
        '3' => ['id' => 3, 'name' => '白色', 'parent_id' => 1],
        '4' => ['id' => 4, 'name' => '黑色', 'parent_id' => 1],
        '5' => ['id' => 5, 'name' => '大', 'parent_id' => 2],
        '6' => ['id' => 6, 'name' => '小', 'parent_id' => 2],
        '7' => ['id' => 7, 'name' => '黄色', 'parent_id' => 3],
        '8' => ['id' => 7, 'name' => '黄色', 'parent_id' => 3],
        '9' => ['id' => 7, 'name' => '黄色', 'parent_id' => 4],
        '10' => ['id' => 7, 'name' => '黄色', 'parent_id' => 5],
    ];


    $treeData = [];// 保存结果
    foreach ($catList as $item) {
        if (isset($catList[$item['parent_id']]) && ! empty($catList[$item['parent_id']])) {// 肯定是子分类
            $catList[$item['parent_id']]['children'][] = &$catList[$item['id']];
        } else {// 肯定是一级分类
            $treeData[] = &$catList[$item['id']];
        }
    }
    dd($treeData);

}