Is there some kind of ordering mechanism in Socket.io that garanties that events are received in order by clients. Exemple : if Server emits event Evt1 to client A, Server broadcasts Evt2 to all clients. thud client A receives Evt1 then Evt2 and only in that order. I am a bit lazy reading the code and can't find my answer on the net. My guess is NO, and if it's the case how would you implement it or is there existing solutions?
No, you have to do that at the application level if you need to do that. The internet doesn't guarantee that two different packets will take the same route, so timing can vary. Maybe add a timestamp to each message so you can sort by that timestamp to keep things in order.