laravel 无限级分类

public function categories()
{
    return $this->hasMany(Category::class, 'parent_id', 'id');
}

public function childrenCategories()
{
    return $this->hasMany(Category::class, 'parent_id', 'id')->with('categories');
}

$categories = Category::where('parent_id', '0')->with('childrenCategories')->get();
// 视图传 $categories

<ul>
    @foreach ($categories as $category)
    <li data-id="{{ $category->id }}"><a href="{{ route('products.lists', $category->id) }}">{{ $category->name }}</a>
        <ul>
            @foreach ($category->childrenCategories as $childCategory)
            @include('product._child_category', ['child_category' => $childCategory])
            @endforeach
        </ul>
    </li>
    @endforeach
</ul>

<li data-id="{{ $child_category->id }}">
    <a href="{{ route('products.lists', $child_category->id) }}">{{ $child_category->name }}</a>
    @if (count($child_category->categories) > 0)
    <ul>
        @foreach ($child_category->categories as $childCategory)
        @include('product._child_category', ['child_category' => $childCategory])
        @endforeach
    </ul>
    @endif
</li>