2 * Implements hook_field_widget_multivalue_form_alter().
4 function {{ machine_name }}_field_widget_multivalue_form_alter(array &$elements, \Drupal\Core\Form\FormStateInterface $form_state, array $context) {
5 // Add a css class to widget form elements for all fields of type mytype.
6 $field_definition = $context['items']->getFieldDefinition();
7 if ($field_definition->getType() == 'mytype') {
8 // Be sure not to overwrite existing attributes.
9 $elements['#attributes']['class'][] = 'myclass';