The next thing that we'll do is configure the server to use Socket.io—that's the entire reason we made this change. Next to the server variable, we'll make a variable called io.
We'll set it equal to a call to socket.io and pass in server, which we want to use with our WebSockets:
var server = http.createServer(app);var io = socketIO(server);
Now we have access to that server via the server variable, so we'll pass it in as the first and only argument. Now, what we get back is our WebSockets server. On here, we can do anything we want in terms of emitting or listening to events. This is how we're going to communicate between the server and the client, and we'll talk more about that later in this section. ...
