getFormKey example

  }

  /** * {@inheritdoc} */
  public function getFormState(ViewEntityInterface $view, $display_id, $js) {
    // $js may already have been converted to a Boolean.     $ajax = is_string($js) ? $js === 'ajax' : $js;
    return (new FormState())
      ->set('form_id', $this->getFormId())
      ->set('form_key', $this->getFormKey())
      ->set('ajax', $ajax)
      ->set('display_id', $display_id)
      ->set('view', $view)
      ->set('type', $this->type)
      ->set('id', $this->id)
      ->disableRedirect()
      ->addBuildInfo('callback_object', $this);
  }

  /** * {@inheritdoc} */