Composition pattern - Menu

_menu.blade.php

<ul class="navbar-nav mr-auto">
    @foreach($items as $item)
        {!! $item->render() !!}
    @endforeach
</ul>

_menu_item.blade.php

@if(count($item->items) > 0)
    <li class="nav-item dropdown">
        <a href="{{ $item->url }}" class="nav-link dropdown-toggle" id="navbar{{ str_slug($item->label) }}" role="button" data-toggle="dropdown" aria-haspopup="true"
           aria-expanded="false">{{ $item->label }}</a>
        <div class="dropdown-menu" aria-labelledby="navbar{{ str_slug($item->label) }}">
            @foreach($item->items as $item)
                {!! $item->render() !!}
            @endforeach
        </div>
    </li>
@else
    @if($item->isSubmenu())
        <a class="dropdown-item" href="{{ $item->url }}">{{ $item->label }}</a>
    @else
        <li class="nav-item">
            <a href="{{ $item->url }}" class="nav-link">{{ $item->label }}</a>
        </li>
    @endif
@endif

MenuComposite.php

<?php

namespace Exdeliver\Causeway\Domain\Entities\Menu;

use Exdeliver\Causeway\Domain\Common\Interfaces\RenderableInterface;
use Illuminate\Contracts\Support\Arrayable;

/**
 * Class MenuComposite
 * @package Exdeliver\Causeway\Domain\Entities\Menu
 */
class MenuComposite implements RenderableInterface
{
    /**
     * @var RenderableInterface
     */
    protected $items;

    /**
     * @return \Illuminate\Contracts\View\View
     */
    public function render(): string
    {
        $items = collect($this->items)
            ->filter(function ($item) {
                return $item->parent_id === null;
            })->map(function ($item) {
                $item = new MenuElementComposite($item);
                return $item;
            });

        return view('causeway::layouts.partials._menu', [
            'items' => $items,
        ]);
    }

    /**
     * @param Arrayable $item
     */
    public function addItem(Arrayable $item)
    {
        $this->items[] = $item;
    }
}

MenuElementComposite.php

<?php

namespace Exdeliver\Causeway\Domain\Entities\Menu;

use Exdeliver\Causeway\Domain\Common\Interfaces\MenuItemInterface;
use Exdeliver\Causeway\Domain\Common\Interfaces\RenderableInterface;

/**
 * Class MenuElementComposite
 * @package Exdeliver\Causeway\Domain\Entities\Menu
 */
class MenuElementComposite implements MenuItemInterface, RenderableInterface
{
    /**
     * @var MenuItemInterface
     */
    protected $item;

    /**
     * MenuElementComposite constructor.
     * @param MenuItemInterface $item
     */
    public function __construct(MenuItemInterface $item)
    {
        if (count($item->items) > 0) {
            $items = $item->items->map(function ($item) {
                $item = new MenuElementComposite($item);
                return $item;
            });
            $item->items = $items;
        }

        $this->item = $item;
    }

    /**
     * @return \Illuminate\Contracts\View\View
     */
    public function render(): string
    {
        return view('causeway::layouts.partials._menu_item', [
            'item' => $this->item,
        ]);
    }

    /**
     * @return bool
     */
    public function isSubmenu()
    {
        return $this->item->isSubmenu();
    }
}

MenuItemInterface.php

<?php

namespace Exdeliver\Causeway\Domain\Common\Interfaces;

/**
 * Interface MenuItemInterface
 * @package Exdeliver\Causeway\Domain\Common\Interfaces
 */
interface MenuItemInterface
{
    public function isSubmenu();
}

RenderableInterface.php

<?php

namespace Exdeliver\Causeway\Domain\Common\Interfaces;

/**
 * Interface RenderableInterface
 * @package Exdeliver\Causeway\Domain\Common\Interfaces
 */
interface RenderableInterface
{
    public function render(): string;
}

        $menuCollection = new MenuComposite();

        foreach($menu->items as $item) {
            $menuCollection->addItem($item);
        }

       $menuCollection->render();