class EditorController

class EditorController extends ControllerBase {
    
    /**
     * Returns an Ajax response to render a text field without transformation filters.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity of which a formatted text field is being rerendered.
     * @param string $field_name
     *   The name of the (formatted text) field that is being rerendered
     * @param string $langcode
     *   The name of the language for which the formatted text field is being
     *   rerendered.
     * @param string $view_mode_id
     *   The view mode the formatted text field should be rerendered in.
     *
     * @return \Drupal\Core\Ajax\AjaxResponse
     *   The Ajax response.
     */
    public function getUntransformedText(EntityInterface $entity, $field_name, $langcode, $view_mode_id) {
        $response = new AjaxResponse();
        // Direct text editing is only supported for single-valued fields.
        $field = $entity->getTranslation($langcode)->{$field_name};
        $editable_text = check_markup($field->value, $field->format, $langcode, [
            FilterInterface::TYPE_TRANSFORM_REVERSIBLE,
            FilterInterface::TYPE_TRANSFORM_IRREVERSIBLE,
        ]);
        $response->addCommand(new GetUntransformedTextCommand($editable_text));
        return $response;
    }
    
    /**
     * Apply the necessary XSS filtering for using a certain text format's editor.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The current request object.
     * @param \Drupal\filter\FilterFormatInterface $filter_format
     *   The text format whose text editor (if any) will be used.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     *   A JSON response containing the XSS-filtered value.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     *   Thrown if no value to filter is specified.
     *
     * @see editor_filter_xss()
     */
    public function filterXss(Request $request, FilterFormatInterface $filter_format) {
        $value = $request->request
            ->get('value');
        if (!isset($value)) {
            throw new NotFoundHttpException();
        }
        // The original_format parameter will only exist when switching text format.
        $original_format_id = $request->request
            ->get('original_format_id');
        $original_format = NULL;
        if (isset($original_format_id)) {
            $original_format = $this->entityTypeManager()
                ->getStorage('filter_format')
                ->load($original_format_id);
        }
        return new JsonResponse(editor_filter_xss($value, $filter_format, $original_format));
    }

}