<?php

namespace App\Notifications;

use App\Mail\NewReplyEmail;
use App\Models\Reply;
use App\Models\Subscription;
use App\User;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Notifications\Notification;

final class NewReplyNotification extends Notification implements ShouldQueue
{
    use Queueable;

    /**
     * @var \App\Models\Reply
     */
    public $reply;

    /**
     * @var \App\Models\Subscription
     */
    public $subscription;

    public function __construct(Reply $reply, Subscription $subscription)
    {
        $this->reply = $reply;
        $this->subscription = $subscription;
    }

    public function via(User $user)
    {
        return ['mail', 'database'];
    }

    public function toMail(User $user)
    {
        return (new NewReplyEmail($this->reply, $this->subscription))
            ->to($user->emailAddress(), $user->name());
    }

    public function toArray(User $user)
    {
        return [
            'type' => 'reply',
            'author' => $this->reply->author(),
            'reply' => $this->reply,
            'thread' => $this->reply->replyAble(),
        ];
    }
}

<?php

namespace App\Notifications;

use App\Mail\NewReplyEmail;
use App\Models\Reply;
use App\Models\Subscription;
use App\User;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Notifications\Notification;

final class NewReplyNotification extends Notification implements ShouldQueue
{
    use Queueable;

    /**
     * @var \App\Models\Reply
     */
    public $reply;

    /**
     * @var \App\Models\Subscription
     */
    public $subscription;

    public function __construct(Reply $reply, Subscription $subscription)
    {
        $this->reply = $reply;
        $this->subscription = $subscription;
    }

    public function via(User $user)
    {
        return ['mail'];
    }

    public function toMail(User $user)
    {
        return (new NewReplyEmail($this->reply, $this->subscription))
            ->to($user->emailAddress(), $user->name());
    }

    public function toArray(User $user)
    {
        return [
            //
        ];
    }
}

--- 
+++ 
@@ -32,7 +32,7 @@
 
     public function via(User $user)
     {
-        return ['mail'];
+        return ['mail', 'database'];
     }
 
     public function toMail(User $user)
@@ -44,7 +44,10 @@
     public function toArray(User $user)
     {
         return [
-            //
+            'type' => 'reply',
+            'author' => $this->reply->author(),
+            'reply' => $this->reply,
+            'thread' => $this->reply->replyAble(),
         ];
     }
 }
Add database notification for new replies
