無窮分類列表 ver 2

Category.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Category extends Model
{

    // 定義 self relation，用來處理子分類
    public function childs()
    {
        return $this->hasMany(self::class, 'of_id');
    }
}

CategoryController.php

<?php

namespace App\Http\Controllers;

use App\Category;
use Illuminate\Http\Request;

use App\Http\Requests;
use App\Http\Controllers\Controller;

class CategoryController extends Controller {
    /**
     * Display a listing of the resource.
     *
     * @return Response
     */
    public function index()
    {
        // 只取得最上層分類，子分類在 view 中處理
        $categories = Category::where( 'of_id', 0 )
                              ->get( [ 'id', 'of_id', 'title' ] );

        return view( 'categories.index', compact('categories') );

    }

}

child.blade.php

<div>
    {{ str_repeat('----', isset($i) ? $i++ : 0) . $category->title }} <br/>

    {{-- 利用 relation 取得子分類，如果有子分類，則逐一遞迴處理 --}}
    @if($childs = $category->childs)
        @foreach($childs as $category)
            @include('categories.child2', ['category' => $category, 'i' => isset($i) ? $i : 1])
        @endforeach
    @endif
    {{-- 子分類 結束 --}}
</div>

index.blade.php

@each('categories.child', $categories, 'category')