server.js

/**
 * This file provided by Facebook is for non-commercial testing and evaluation
 * purposes only. Facebook reserves all rights not expressly granted.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

var fs = require('fs');
var path = require('path');
var express = require('express');
const http = require('http');
const morgan = require('morgan');
const socketio = require('socket.io');
var bodyParser = require('body-parser');
var reactViews = require('express-react-views');
var errorHandler = require('errorhandler');
//create the instances
var app = express();
const server = http.createServer(app);
const io = socketio(server);

var React = require('react');
var ReactDOMServer = require('react-dom/server');

//different functionalities for maintaining different chat rooms
const formatMessage = require('./utils/messages');
const {
  userJoin,
  getCurrentUser,
  userLeave,
  getRoomUsers
} = require('./utils/users');



// the bot would inform about activites in room
const botName = 'ChatCord Bot';

app.set('views', __dirname + '/views');
app.set('view engine', 'jsx');
var options = { 
  transformViews:true,
 };
app.engine('jsx', reactViews.createEngine(options));

app.use('/', express.static(path.join(__dirname, 'public')));

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

// development only
if ('development' == app.get('env')) {
  app.use(errorHandler());
}

// Additional middleware which will set headers that we need on each request.
app.use(function (req, res, next) {
  // Set permissive CORS header - this allows this server to be used only as
  // an API server in conjunction with something like webpack-dev-server.
  res.setHeader('Access-Control-Allow-Origin', '*');

  // Disable caching so we'll always get the latest comments.
  res.setHeader('Cache-Control', 'no-cache');
  next();
});
//make a universal error middle ware with app.use()

// middleware for logging in the dev mode only -- not for productions
app.use(morgan('dev'));
// importing routes
const indexRoutes = require('./routes/index');

// routes
app.use('/', indexRoutes);

// Run when client connects
io.on('connection', socket => {
  socket.on('joinRoom', ({ username, room }) => {
    const user = userJoin(socket.id, username, room);

    socket.join(user.room);

    // Welcome current user
    socket.emit('message', formatMessage(botName, 'Welcome to ChatCord!'));

    // Broadcast when a user connects
    socket.broadcast
      .to(user.room)
      .emit(
        'message',
        formatMessage(botName, `${user.username} has joined the chat`)
      );

    // Send users and room info
    io.to(user.room).emit('roomUsers', {
      room: user.room,
      users: getRoomUsers(user.room)
    });
  });

  // Listen for chatMessage
  socket.on('chatMessage', msg => {
    const user = getCurrentUser(socket.id);

    io.to(user.room).emit('message', formatMessage(user.username, msg));
  });

  // Runs when client disconnects
  socket.on('disconnect', () => {
    const user = userLeave(socket.id);

    if (user) {
      io.to(user.room).emit(
        'message',
        formatMessage(botName, `${user.username} has left the chat`)
      );

      // Send users and room info
      io.to(user.room).emit('roomUsers', {
        room: user.room,
        users: getRoomUsers(user.room)
      });
    }
  });
});
// get port from parameter listings or do start in default port
const PORT = process.env.PORT || 3000;
app.listen(PORT, ()=> {
  console.log('Server started: http://localhost:' + PORT + '/');
});