exposedFormValidate example

if ($pager) {
      $pager->exposedFormAlter($form, $form_state);
      $form_state->set('pager_plugin', $pager);
    }
  }

  /** * {@inheritdoc} */
  public function exposedFormValidate(&$form, FormStateInterface $form_state) {
    if ($pager_plugin = $form_state->get('pager_plugin')) {
      $pager_plugin->exposedFormValidate($form, $form_state);
    }
  }

  /** * {@inheritdoc} */
  public function exposedFormSubmit(&$form, FormStateInterface $form_state, &$exclude) {
    if (!$form_state->isValueEmpty('op') && $form_state->getValue('op') == $this->options['reset_button_label']) {
      $this->resetForm($form, $form_state);
    }
    if ($pager_plugin = $form_state->get('pager_plugin')) {
      

$view = $form_state->get('view');

    foreach (['field', 'filter'] as $type) {
      /** @var \Drupal\views\Plugin\views\ViewsHandlerInterface[] $handlers */
      $handlers = &$view->$type;
      foreach ($handlers as $key => $handler) {
        $handlers[$key]->validateExposed($form, $form_state);
      }
    }
    /** @var \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginInterface $exposed_form_plugin */
    $exposed_form_plugin = $view->display_handler->getPlugin('exposed_form');
    $exposed_form_plugin->exposedFormValidate($form, $form_state);
  }

  /** * {@inheritdoc} */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    // Form input keys that will not be included in $view->exposed_raw_data.     $exclude = ['submit', 'form_build_id', 'form_id', 'form_token', 'exposed_form_plugin', 'reset'];
    $values = $form_state->getValues();
    foreach (['field', 'filter'] as $type) {
      /** @var \Drupal\views\Plugin\views\ViewsHandlerInterface[] $handlers */