username or email validation in laravel
$input = $request->only('account'); // dont use all(), ever
            
$rules = [
  'account' => 'required'
];
if (filter_var($input['account'], FILTER_VALIDATE_EMAIL)) {
  $rules['account'] .= '|exists:users,email';
} else {
  $rules['account'] .= '|exists:users,username';
}
$messages = [
  'account.required' => 'Enter username or email to login.',                
];
$validator = Validator::make($input, $rules, $messages);
