Answers for "laravel request validation optional parameter"

if any error in blade laravel

@if ($errors->any())
     @foreach ($errors->all() as $error)
         <div>{{$error}}</div>
     @endforeach
 @endif

laravel validation

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\Validator;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }

    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Validator::extend('foo', function ($attribute, $value, $parameters, $validator) {
            return $value == 'foo';
        });
    }
}