materio-d8/web/modules/custom/materio_user/materio_user.module

<?php

/**
 * @file
 * Contains materio_user.module.
 */

use \Drupal\Core\Form\FormStateInterface;
use \Drupal\Core\Block\BlockPluginInterface;
use \Drupal\Core\Url;
use \Drupal\Core\Link;
use \Drupal\materio_user\MaterioUserLoginBlockAlterRender;
/**
 * implements hook_form_FORM_ID_alter()
 *
 */
function materio_user_form_user_login_form_alter(&$form, FormStateInterface $form_state, $form_id) {

  $form['name']['#attributes'] += array(
    "v-model" => "mail",
    "title" => "",
    // "@keyup.enter" => "login"
  );

  $form['pass']['#attributes'] = array(
    "v-model" => "password",
    "title" => "",
    // "@keyup.enter" => "login"
  );

  $url = Url::fromRoute('user.pass');
  $form['pass']['#description'] = Link::fromTextAndUrl(t('Forgot your password?'), $url)->toString();
  // "<a href="{{ path('user.pass') }}">{{ 'Forgot your password?'|t }}</a>";

  $form['actions']['submit']['#attributes'] = array(
    "@click.prevent" => "login"
  );

  $form['message'] = array(
    '#weight' => -10,
    '#markup' => '
      <span class="login-message" v-if="loginMessage">
        {{ loginMessage }}
      </span>
    '
  );

}

function materio_user_form_user_modal_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $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",
    "ref" => "register"
    // ":class" => "can_register"
  );

  $form['account']['message'] = array(
    '#weight' => -10,
    '#markup' => '
      <span class="register-message" v-if="registerMessage">
        {{ registerMessage }}
      </span>
    '
  );
}

function _materio_user_process_password_confirm($element){
  // ksm($element);
  $element['pass1']['#description'] = t('Password must contains height lowercase, uppercase, digits and special characters.');
  $element['pass1']['#attributes'] += array(
    "v-model" => "pass1",
    "placeholder" => $element['pass1']['#title'],
    ":class" => "psswd_class"
  );
  $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()
 *
 * OLD D8 https://www.drupal.org/project/drupal/issues/2626224
 * NEW D9 https://www.drupal.org/node/2966725
 */
function materio_user_block_view_user_login_block_alter(array &$build, BlockPluginInterface $block) {
  // $build['#pre_render'][] = '_materio_user_user_login_block_pre_render';
  $build['#pre_render'][] = [MaterioUserLoginBlockAlterRender::class, 'preRender'];
}

function _materio_user_user_login_block_pre_render(array $build){
  $user_links = &$build['content']['user_links'];
  $items = &$user_links['#items'];

  unset($items['create_account']);
  // $items['create_account']['#url']->mergeOptions(array(
  //   "attributes" => array(
  //     "@click.prevent" => "create_account"
  //   )
  // ));

  // Do not handle passward reset with vue
  // $items['request_password']['#url']->mergeOptions(array(
  //   'attributes' => array(
  //     "@click.prevent" => "request_password"
  //   )
  // ));
  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');
}

/*
* hook_menu_local_tasks_alter
*/
function materio_user_menu_local_tasks_alter(&$data, $route_name){
  $t="t";
  // remove some tabs on user pages
  // if (in_array($route_name, ['entity.user.canonical', 'entity.user.edit_form']) ) {
  if (preg_match('/^entity\.user\./', $route_name)
    || in_array($route_name, [
      'simplenews.newsletter_subscriptions_user',
      'commerce_order.address_book.overview',
      'entity.commerce_payment_method.collection',
      'view.commerce_user_orders.order_page',
      'view.commerce_user_subscriptions.page_1'
      ])) {
    unset($data['tabs'][0]['profile.user_page:member']);
    $data['tabs'][0]['entity.user.edit_form']['#weight'] = -20;
    $data['tabs'][0]['simplenews.newsletter_subscriptions_user']['#weight'] = -9;
  }
  // foreach ($data['tabs'] as $key => $tab) {
  //   if ($key == 'profile.user_page:member') {
  //     unset($data['tabs'][$key]);
  //   }
  //   if ($key == 'entity.user.edit_form') {
  //     $data['tabs'][$key]['#weight'] = -200;
  //   }
  //
  // }
}

/*
* hook_local_tasks_alter
*/
// function materio_user_local_tasks_alter(&$local_tasks){
//   $t="t";
// }

function materio_user_form_alter(array &$form, FormStateInterface $forme_state, $form_id){
  if ($form_id == 'simplenews_subscriber_account_form') {
    $user = \Drupal::currentUser();
    $roles = $user->getRoles();
    $t="t";
    if (in_array('adherent', $roles)) {
      unset($form['subscriptions']['widget']['#options']['companies']);
      unset($form['subscriptions']['widget']['#options']['test']);
    }
  }
}