How to determine that io is running?

Question

Node.js

When starting the application, I want to be sure that the socket io is attached to the server and ready to accept requests. Actually, how to do it? Does io have an analogue of once open, like mongo?
I run it like this:io = require('socket.io')(server);

Answer 1

socket.io just hangs a handler on server. When server starts then io starts.
You can find out when the server starts in the callback of the listen method.