code: public function showFlashMessages($sticky = false)
      {
          $timeout = $sticky ? 0 : 5000;
          $flashMessages = [];
          $allMessages = $this->getSession()->getAllFlashes();
          foreach ($allMessages as $key => $message) {
              if (is_array($message)) {
                  $message = $this->mergeFlashMessages($message);
              }
              $flashMessages[] = [
                  'message' => $message,
                  'type' => $key,
                  'timeout' => $timeout
              ];
          }
          $this->getSession()->removeAllFlashes();
          return Html::script('var notifications =' . json_encode($flashMessages));
      }
docs: show flash messages
  @author Adeyemi Olaoye <yemi@cottacush.com>
  @param bool $sticky
  @return string