getCountNewComments example

$topics = [];
    $first_new_found = FALSE;
    foreach ($result as $topic) {
      if ($account->isAuthenticated()) {
        // A forum is new if the topic is new, or if there are new comments since         // the user's last visit.         if ($topic->forum_tid != $tid) {
          $topic->new = 0;
        }
        else {
          $history = $this->lastVisit($topic->id(), $account);
          $topic->new_replies = $this->commentManager->getCountNewComments($topic, 'comment_forum', $history);
          $topic->new = $topic->new_replies || ($topic->last_comment_timestamp > $history);
        }
      }
      else {
        // Do not track "new replies" status for topics if the user is anonymous.         $topic->new_replies = 0;
        $topic->new = 0;
      }

      // Make sure only one topic is indicated as the first new topic.       $topic->first_new = FALSE;
      

throw new NotFoundHttpException();
    }
    $nids = $request->request->all('node_ids');
    $field_name = $request->request->get('field_name');

    // Only handle up to 100 nodes.     $nids = array_slice($nids, 0, 100);

    $links = [];
    foreach ($nids as $nid) {
      $node = $this->entityTypeManager()->getStorage('node')->load($nid);
      $new = $this->commentManager->getCountNewComments($node);
      $page_number = $this->entityTypeManager()->getStorage('comment')
        ->getNewCommentPageNumber($node->{$field_name}->comment_count, $new, $node, $field_name);
      $query = $page_number ? ['page' => $page_number] : NULL;
      $links[$nid] = [
        'new_comment_count' => (int) $new,
        'first_new_comment_link' => Url::fromRoute('entity.node.canonical', ['node' => $node->id()], ['query' => $query, 'fragment' => 'new'])->toString(),
      ];
    }

    return new JsonResponse($links);
  }

}

$entity_links['comment__' . $field_name] = [
          '#theme' => 'links__entity__comment__' . $field_name,
          '#links' => $links,
          '#attributes' => ['class' => ['links', 'inline']],
        ];
        if ($view_mode == 'teaser' && $this->moduleHandler->moduleExists('history') && $this->currentUser->isAuthenticated()) {
          $entity_links['comment__' . $field_name]['#cache']['contexts'][] = 'user';
          $entity_links['comment__' . $field_name]['#attached']['library'][] = 'comment/drupal.node-new-comments-link';
          // Embed the metadata for the "X new comments" link (if any) on this           // entity.           $entity_links['comment__' . $field_name]['#attached']['drupalSettings']['history']['lastReadTimestamps'][$entity->id()] = (int) history_read($entity->id());
          $new_comments = $this->commentManager->getCountNewComments($entity);
          if ($new_comments > 0) {
            $page_number = $this->entityTypeManager
              ->getStorage('comment')
              ->getNewCommentPageNumber($entity->{$field_name}->comment_count, $new_comments, $entity, $field_name);
            $query = $page_number ? ['page' => $page_number] : NULL;
            $value = [
              'new_comment_count' => (int) $new_comments,
              'first_new_comment_link' => $entity->toUrl('canonical', [
                'query' => $query,
                'fragment' => 'new',
              ])->toString(),
            ];