public static function addMoreSubmit(array $form, FormStateInterface $form_state) {
$button = $form_state
->getTriggeringElement();
// Go one level up in the form, to the widgets container.
$element = NestedArray::getValue($form, array_slice($button['#array_parents'], 0, -2));
$field_name = $element['#field_name'];
$parents = $element['#field_parents'];
// Increment the items count.
$widget_state = static::getWidgetState($parents, $field_name, $form_state);
if ($widget_state['real_item_count'] < $element['#cardinality'] || $element['#cardinality'] == FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED) {
$widget_state['items_count']++;
}
if (isset($button['#bundle_machine_name'])) {
$widget_state['selected_bundle'] = $button['#bundle_machine_name'];
}
else {
$widget_state['selected_bundle'] = $element['add_more']['add_more_select']['#value'];
}
static::setWidgetState($parents, $field_name, $form_state, $widget_state);
$form_state
->setRebuild();
}