laravel error message show code example

Example 1: how to add an custom error to validater error in laravel

if (request('event') == null) {
    $validator->errors()->add('event', 'Please select an event');
}

Example 2: laravel return validation errors

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