When can be socket client disconnected

Question

please look at the code below. It's a simple program in nodeJS. Question is why disconnect is not printed? (If you uncomment setTimeout, problem is gone) What is the real question?: Why can't I start socketIO client and server together and close a socket immediately after connection? What is the know-how regarding connections with socketIO?

"use strict";
var Promise = require("bluebird");
var socketio = require("socket.io");
var socketio_client = require("socket.io-client");
var http = require("http");

var port = 7457;
var hostandport = "http://localhost:" + port.toString();

var server = socketio.listen(port);

var client = socketio_client(hostandport);

server.sockets.on("connect", function (socket) {
    console.log("connect");
    socket.on("disconnect", function () {
        console.log("disconnect");
    });

    //setTimeout(function() {
        client.disconnect();
    //}, 1000);
});

Answer 1

You have set up your server incorrectly, do this instead:

var server = require('http').createServer(handler);
var io = require('socket.io')(server);

io.on("connect", function (socket) {
    console.log("connect");
    socket.on("disconnect", function () {
        console.log("disconnect");
    });
//More importantly, you have done this part wrong, 
//the rest of your code may be functional, 
//but it does not adhere to what socket.io sets out in its own API
//(http://socket.io/docs/)
        socket.disconnect();
});

Answer 2

In Socket.io there is no such thing as connection on server side and/or browser side. There is only one connection. If one of the sides closes it, then it is closed. So you can close it from Server using socket.disconnect()

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);

io.on('connection', function(socket){
  console.log('a user connected');
  socket.on('disconnect', function(){
    console.log('user disconnected');
  });
  setTimeout(function() {
    socket.disconnect();
  }, 1000);
});

Goto http://socket.io/get-started/chat/ for more clarifications.