mint/api-v13/app/Http/Resources/ChatResource.php

<?php

namespace App\Http\Resources;

use Illuminate\Contracts\Support\Arrayable;
use Illuminate\Http\Request;
use Illuminate\Http\Resources\Json\JsonResource;

class ChatResource extends JsonResource
{
    /**
     * Transform the resource into an array.
     *
     * @param  Request  $request
     * @return array|Arrayable|\JsonSerializable
     */
    public function toArray($request)
    {
        return [
            'id' => $this->uid,
            'title' => $this->title,
            'user_id' => $this->user_id,
            'created_at' => $this->created_at,
            'updated_at' => $this->updated_at,
            'messages_count' => $this->when($this->relationLoaded('messages'), function () {
                return $this->messages->count();
            }),
        ];
    }
}