refactor code style and code review

app/Livewire/Chat/MessageWindow.php

@@ -5,9 +5,9 @@ namespace App\Livewire\Chat;
 use App\Events\ChatMessageUpdated;
 use App\Models\Chat;
 use App\Models\User;
-use Livewire\Component;
-use Illuminate\View\View;
 use Illuminate\Support\Collection;
+use Illuminate\View\View;
+use Livewire\Component;
 
 class MessageWindow extends Component
 {
@@ -21,7 +21,7 @@ class MessageWindow extends Component
 
     public User|null $recipientUser = null;
 
-    public  string $chanId;
+    public string $chanId;
 
     public User $curUser;
 
@@ -43,7 +43,7 @@ class MessageWindow extends Component
             ->prepend($message);
     }
 
-    public function updateRecipientId(int $id = null): void
+    public function updateRecipientId(?int $id = null): void
     {
     }
 
@@ -60,7 +60,7 @@ class MessageWindow extends Component
     }
 
     // FIXME
-    public function mount(int $recipientUserId = null): void
+    public function mount(?int $recipientUserId = null): void
     {
         $this->recipientUserId = $recipientUserId;
         $this->recipientUser = User::find($recipientUserId);