materio expo added email validation, file without email redirect to form

web/modules/custom/materio_expo/src/Form/GetEmail.php

@@ -7,12 +7,38 @@ use Drupal\Core\Form\FormStateInterface;
 // use Symfony\Component\HttpFoundation\Cookie;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 use Drupal\Core\Url;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Egulias\EmailValidator\EmailValidator;
 
 /**
  * Class GetEmail.
  */
 class GetEmail extends FormBase {
 
+ /**
+   * The email validator.
+   *
+   * @var \Egulias\EmailValidator\EmailValidator
+   */
+  protected $emailValidator;
+
+  /**
+   * Constructs 
+   *
+   * @param \Egulias\EmailValidator\EmailValidator $email_validator
+   *   The email validator.
+   */
+  public function __construct(EmailValidator $email_validator) {
+    $this->emailValidator = $email_validator;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static($container->get('email.validator'));
+  }
+
   /**
    * {@inheritdoc}
    */
@@ -80,6 +106,14 @@ class GetEmail extends FormBase {
    */
   public function validateForm(array &$form, FormStateInterface $form_state) {
     parent::validateForm($form, $form_state);
+    $values = $form_state->getValues();
+    if (!$this->emailValidator->isValid($values['email'])) {
+      $form_state->setErrorByName('email',
+        $this->t('%email is an invalid email address.', [
+          '%email' => $values['email'],
+        ])
+      );
+    }
   }
 
   /**