connecting refused for web socket socket.io - node.js

Question

I am loading my scripts using
<script src="https://cdn.socket.io/socket.io-1.4.5.js"></script>
<script src="/js/chat.js"></script>
My chat.js script is :
var socket = io();
socket.on('connect', function(){
var chatForm = document.forms.chatForm;
if (chatForm) {
var chatUsername = document.querySelector('#chat-username');
var chatMessage = document.querySelector('#chat-message');
chatForm.addEventListener("submit", function(e){
console.log("working")
//prevents page from reloading
e.preventDefault();
//emit the message with the socket
socket.emit('postMessage',{
username: chatUsername.value,
message: chatMessage.value,
});
chatMessage.value='';
chatMessage.focus();
});//chatform event
socket.on('updateMessages', function(data) {
showMessage(data);
});//update messages
}//chatForm
})
function showMessage(data) {
var chatDisplay = document.querySelector('.chat-display')
var newMessage = document.createElement('p');
newMessage.className = 'bg-success chat-text';
newMessage.innerHTML = '<strong>' + data.username + '<strong>:</strong>' +
data.message
chatDisplay.insertBefore(newMessage, chatDisplay.firstChild);
}
My app.js file uses:
app.set('port', process.env.PORT || 3000 );
var server = app.listen(app.get('port'), function() {
console.log('Listening on port ' + app.get('port'));
});
io.attach(server);
io.on('connection', function(socket) {
console.log("user connected");
socket.on('postMessage', function(data) {
io.emit('updateMessages', data);
});
});
I am getting the following errors in my console and have no idea how to fix them. Somebody please help!
The server is listening on port 3000. My console is saying that there is an unhandled 'error' event

Answer 1

In your app.js file, you should connect socketIO before listening:
const socketIO = require('socket-io');
const io = socketIO(app);
io.on('connection', function(socket) {
console.log("user connected");
socket.on('postMessage', function(data) {
io.emit('updateMessages', data);
});
});
app.set('port', process.env.PORT || 3000 );
app.listen(app.get('port'), function() {
console.log('Listening on port ' + app.get('port'));
});
Let try it, because I think after listening, everything won't work. We should connect socketIO before listening.