AjaxRenderer::renderResponse

public AjaxRenderer::renderResponse(array $main_content, Request $request, RouteMatchInterface $route_match)

public function renderResponse(array $main_content, Request $request, RouteMatchInterface $route_match) {
  $response = new AjaxResponse();

  if (isset($main_content['#type']) && ($main_content['#type'] == 'ajax')) {
    // Complex Ajax callbacks can return a result that contains an error
    // message or a specific set of commands to send to the browser.
    $main_content += $this->elementInfoManager->getInfo('ajax');
    $error = $main_content['#error'];
    if (!empty($error)) {
      // Fall back to some default message otherwise use the specific one.
      if (!is_string($error)) {
        $error = 'An error occurred while handling the request: The server received invalid input.';
      }
      $response->addCommand(new AlertCommand($error));
    }
  }

  $html = $this->drupalRenderRoot($main_content);
  $response->setAttachments($main_content['#attached']);

  // The selector for the insert command is NULL as the new content will
  // replace the element making the Ajax call. The default 'replaceWith'
  // behavior can be changed with #ajax['method'].
  $response->addCommand(new InsertCommand(NULL, $html));
  $status_messages = array('#type' => 'status_messages');
  $output = $this->drupalRenderRoot($status_messages);
  if (!empty($output)) {
    $response->addCommand(new PrependCommand(NULL, $output));
  }
  return $response;
}