How to bring MenuWidget into a divine form?

Question

Yii

Hello. The widget does not collapse.

<?php

namespace app\components;

use yii\base\Widget;
use app\models\Category;
use Yii;

class MenuWidget extends Widget{
    public $tpl;
    public $model;
    public $data;
    public $tree;
    public $menuHtml;
    public function init(){
        parent::init();
        if( $this->tpl === null ){
            $this->tpl = 'menu';
        }
        $this->tpl .= '.php';
    }
    public function run(){

        if($this->tpl == 'menu.php'){
            $menu = Yii::$app->cache->get('menu');
            if($menu) return $menu;
        }
        $this->data = Category::find()->indexBy('id')->asArray()->all();
        $this->tree = $this->getTree();
        $this->menuHtml = $this->getMenuHtml($this->tree);

        if($this->tpl == 'menu.php'){
            Yii::$app->cache->set('menu', $this->menuHtml, 60);
        }
        return $this->menuHtml;
    }
    protected function getTree(){
        $tree = [];
        foreach ($this->data as $id=>&$node) {
            if (!$node['parent_id'])
                $tree[$id] = &$node;
            else
                $this->data[$node['parent_id']]['children'][$node['id']] = &$node;
        }
        return $tree;
    }
    protected function getMenuHtml($tree, $tab = ''){
        $str = '';
        foreach ($tree as $category) {
            $str .= $this->catToTemplate($category, $tab);
        }
        return $str;
    }
    protected function catToTemplate($category, $tab){
        ob_start();
        include __DIR__ . '/menu_tpl/' . $this->tpl;
        return ob_get_clean();
    }
}