The code is in src/socket.io/posts.js, but I can't find the topic_id and app.currentRoom you mention.
Rethinking sending notifications on voting
Notifications are sent when users' posts are up/down-voted. While this looks like a cool feature, it seems more like the easiest way to build bad blood on a forum.
If I receive a down-vote and I'm told who the culprit is, there's a tendency that I'll be looking for an opportunity to return the (dis)favor. I think voting should be an anonymous activity. If notifications have to be sent, it'd be better if they are as generic as posible. For example, instead of "user1 has down-voted your post", say, "your post has been down-voted".
Actually you get a notification only when someone ups or favourites your posts, you don't get a notification on downvote and unfavourite.
Ok, that's good to know. It's just that the discussion at get notifications when someone up or downs your post #1184 didn't clarify that.