I was wondering how can I add
this emoji window to a meteor app.
It is supposed to run on desktop only
Basically, what you need to do is to steal it from Discourse.
The forum code is not part of Meteor platform, it’s a separate forum webapp made with Ember&Rails. So it’s not like there’s a Meteor package for this emoji window that you can simply add.
You may start here: http://www.emoji-cheat-sheet.com/