JeroenNoten\LaravelAdminLte\Menu\Builder::transformItems PHP Method

    public function transformItems($items)
    {
        return array_filter(array_map([$this, 'applyFilters'], $items));
    }

 public function transform($item, Builder $builder)
 {
     if (isset($item['submenu'])) {
         $item['submenu'] = $builder->transformItems($item['submenu']);
         $item['submenu_open'] = $item['active'];
         $item['submenu_classes'] = $this->makeSubmenuClasses();
         $item['submenu_class'] = implode(' ', $item['submenu_classes']);
     }
     return $item;
 }