applicant-site/app/Http/Requests/admin/Catalog/UpdateDepartmentRequest.php

<?php

namespace App\Http\Requests\admin\Catalog;

use Illuminate\Foundation\Http\FormRequest;

class UpdateDepartmentRequest extends FormRequest
{
    public function authorize(): bool
    {
        return true;
    }
    public function rules(): array
    {
        return [
            'position' => 'required|int|max:255',
            'description' => 'string',
            'slug' => 'string|required',
            'faculty_id' => 'int|required',
            'name' => [
                'required',
                'string',
                'max:255',
                "unique:departments,name,{$this->department->id}",
            ],
        ];
    }
}