buildAttachmentsCommands example

  /** * {@inheritdoc} */
  public function processAttachments(AttachmentsInterface $response) {
    assert($response instanceof AjaxResponse, '\Drupal\Core\Ajax\AjaxResponse instance expected.');

    $request = $this->requestStack->getCurrentRequest();

    if ($response->getContent() == '{}') {
      $response->setData($this->buildAttachmentsCommands($response, $request));
    }

    return $response;
  }

  /** * Prepares the AJAX commands to attach assets. * * @param \Drupal\Core\Ajax\AjaxResponse $response * The AJAX response to update. * @param \Symfony\Component\HttpFoundation\Request $request * The request object that the AJAX is responding to. * * @return array * An array of commands ready to be returned as JSON. */