Emitting to a room can't work with CoffeeScript since "in" is a key word in CS.

[OrionChang]

Emitting an event to all clients in a particular room

io.sockets.in('room').emit('event_name', data)

will be compiled to

io.sockets"in".emit('event_name', data)

[tr00per]

This looks more like a CoffeeScript issue. This "in" should be treated as a function call. It's a parsing inaccuracy in CS. "In" is also a keyword in JS and it's not complaining.

[prajwalkman]

You should be able to use io.sockets['in']('room').emit('event_name', data) while Jashkenas fixes this.

[prajwalkman]

Oops; It's already fixed in the latest coffeescript release: 1.6.2