#3458839 fix warnings

src/Element/RutField.php

@@ -63,7 +63,7 @@ class RutField extends Textfield {
       $element['#attached']['library'][] = 'rut/rut.rut';
 
       $element['#attributes']['class'][] = 'rut-validate-js';
-      $message = trim($element['#message_js']) != '' ? $element['#message_js'] : t('Invalid Rut');
+      $message = isset($element['#message_js']) && trim($element['#message_js']) != '' ? trim($element['#message_js']) : t('Invalid Rut');
       $extra = '<div class="error-message-js invisible">' . $message . '</div>';
       $element['#children']['extra']['#markup'] = $extra;
       if ($element['#bypass_validation']) {