Socket.io (server+client) and Express based Sample chat system

client.js

/**
* Socket io client
* */
socket = require('socket.io-client')(window.location.hostname + ':9090');

/**
 * Chat Functionalities
 */
chat = {
    addMessageElement: (element) => {
        // Add Message DOM element using element var info
    },

    pushMessageToSocket: () => {
        var data = {
            message: $("#chatTextarea").val().trim()
        };

        socket.emit('chat-message', data);
        $("#chatTextarea").val('');
    }
};

/**
 * Events
 * */
require('event-handler');

event-handler.js

socket.on('connect', () => {
    // User connected
});
socket.on('chat-message', (data) => {
    chat.addMessageElement(data);
});
socket.on('disconnect', () => {
    // User disconnected
});

socket-io-server.js

const express = require('express')();
const server = require('http').Server(express);
const io = require('socket.io')(server);

io.on('connection', function (socket) {

    console.log("new client connected");

    socket.on('chat-message', function (data) {
        io.emit('chat-message', data);
    });

    socket.on('user-join', function(data) {
        io.emit('user-join', data);
    });

    socket.on('disconnect', function(data) {
    });
});

server.listen(9090, function () {
    console.log('socket.io server listen at 9090');
});