handeled login or register from a modal, YES git status

web/modules/custom/materio_user/materio_user.module

@@ -30,6 +30,67 @@ function materio_user_form_user_login_form_alter(&$form, FormStateInterface $for
 
 }
 
+function materio_user_form_user_modal_form_alter(&$form, FormStateInterface $form_state, $form_id) {
+  // Drupal::logger('materio_user')->notice(print_r($form['mail'], true));
+  // ksm($form);
+  $form['account']['mail']['#attributes'] = array(
+    "v-model" => "mail",
+    "@keyup.enter" => "register",
+    "placeholder" => $form['account']['mail']['#title'],
+    "title" => $form['account']['mail']['#description']
+  );
+
+  // https://drupal.stackexchange.com/a/217112
+  // Get default process function array:
+  $element_info = element_info('password_confirm');
+  $process = $element_info['#process'];
+  // Add our process function to the array:
+  $process[] = '_materio_user_process_password_confirm';
+  $form['account']['pass']['#process'] = $process;
+
+  $form['actions']['submit']['#attributes'] = array(
+    "@click.prevent" => "register",
+    "@keyup.enter" => "register"
+  );
+
+}
+
+function _materio_user_process_password_confirm($element){
+  // ksm($element);
+  $element['pass1']['#attributes'] += array(
+    "v-model" => "pass1",
+    "placeholder" => $element['pass1']['#title']
+  );
+  $element['pass2']['#attributes'] += array(
+    "v-model" => "pass2",
+    "placeholder" => $element['pass2']['#title']
+
+  );
+  return $element;
+}
+/**
+ * Returns HTML for a form element.
+ * Prepares variables for form element templates.
+ *
+ * Default template: form-element.html.twig.
+ *
+ * @param array $variables
+ *   An associative array containing:
+ *   - element: An associative array containing the properties of the element.
+ *     Properties used: #title, #title_display, #description, #id, #required,
+ *     #children, #type, #name, #label_for.
+ */
+// function materio_user_preprocess_form_element(&$vars) {
+//   $element = $vars['element'];
+//   if($element['#type'] == 'password' && $element['#array_parents'][0] == 'account'){
+//     ksm($vars);
+//     // $vars['attributes']['placeholder'] = $element['#title'];
+//     $vars['element']['#attributes']['placeholder'] = $element['#title'];
+//   }
+// }
+
+
+
 /**
  * implements hook_block_view_BASE_BLOCK_ID_alter()
  *
@@ -55,3 +116,8 @@ function _materio_user_user_login_block_pre_render(array $build){
   ));
   return $build;
 }
+
+function materio_user_entity_type_build(array &$entity_types) {
+  // https://drupal.stackexchange.com/a/230547
+  $entity_types['user']->setFormClass('modal', 'Drupal\user\RegisterForm');
+}

web/modules/custom/materio_user/src/Controller/AjaxRegisterForm.php

@@ -44,12 +44,13 @@ class AjaxRegisterForm extends ControllerBase {
   }
 
   private function getFormDefinition(){
-    // $language = \Drupal::languageManager()->getCurrentLanguage()->getId();
-    // \Drupal::logger('materio_user')->notice($language);
-    // $this->form_builded = $this->formBuilder->getForm('Drupal\user\Form\UserLoginForm');
-    $entity = \Drupal::entityTypeManager()->getStorage('user')->create(array());
+    // http://web-tricks.org/content/how-render-user-login-form-and-user-register-form-drupal-8
+    $entity = \Drupal::entityTypeManager()
+      ->getStorage('user')
+      ->create(array());
+    // to use modal form display see materio_user_entity_type_build()
     $formObject = \Drupal::entityTypeManager()
-      ->getFormObject('user', 'register')
+      ->getFormObject('user', 'modal')
       ->setEntity($entity);
     $this->form_builded = $this->formBuilder()->getForm($formObject);
   }