Laravel 8中如何保持下拉筛选框选中选项的状态？

背景 #

我用Laravel 8开发了一个博客应用，文章支持评论功能，评论需经管理员审核后才可发布。我添加了一个下拉选择框，用于按状态筛选评论或显示全部评论：

<form class="d-flex align-items-center" method="get" action="{{ route('dashboard.comments')}}">
  <label for="commentsFilter" class="form-label mb-0 me-1">Filter</label>
  <select class="form-select" id="commentsFilter" name="filter" onchange="this.form.submit()">
     @foreach ($filters as $filter)
       <option value="{{ $filter->value }}" {{ $active_filter == $filter->value ? 'selected' : '' }}>{{ $filter->label }}</option>
    @endforeach
  </select>
</form>

控制器代码 #

CommentController的index方法代码如下：

class CommentController extends Controller
{

  public function index(Request $request)
  {
    // 评论总数
    $comments_count =  Comment::count();

    // 未审核评论数
    $unapproved_comments_count = Comment::where('approved', 0)->count();

    // 每页显示评论数
    $per_page = 10;

    // 筛选选项
    $filters = $filter = [
      (object)[
        'value' => 'all',
        'label' => 'All comments'
      ],
      (object)[
        'value' => 0,
        'label' => 'Unapproved'
      ],
      (object)[
        'value' => 1,
        'label' => 'Approved'
      ]
    ];

    // 从URL获取当前筛选器
     $active_filter = $request->query('filter');
   

    // 按筛选条件获取评论
    $filter = $request->input('filter');

    $comments = Comment::orderBy('id', 'desc')
      ->when($filter !== 'all', function ($query) use ($filter) {
        return $query->where('approved', $filter);
      }, function ($query) {
        return $query->where('approved', 1)->orWhere('approved', 0);
      })
      ->paginate($per_page)->onEachSide(1);

    return view(
      'dashboard/article-comments',
        [
          'per_page' => $per_page,
          'current_page' => $comments->currentPage(),
          'comments' => $comments,
          'comments_count' => $comments_count,
          'unapproved_comments_count' => $unapproved_comments_count,
          'filters' => $filters,
          'active_filter' => $active_filter,
        ]
      );
  }
}

问题 #

当选择查看全部评论时，<option value="all">All comments</option>选项无法保持选中状态，但另外两个选项选择后可以正常保持选中。我尝试修改获取活跃筛选器的代码为以下内容，但仍然无效：

// 从URL获取当前筛选器
if (isset($active_filter) && !is_null($active_filter)) {
     $active_filter = $request->query('filter');
} else {
     $active_filter = 'all';
}

请问如何在URL为dashboard/comments?filter=all时，保持「All comments」选项处于选中状态？

内容的提问来源于stack exchange，提问作者Razvan Zamfir