server.js

const path = require('path');
const http = require('http');
const express = require('express');
const socketio = require('socket.io');
const formatMessage = require('./utils/messages');
const {userJoin, getCurrentUser, userLeaves, getRoomUsers} = require('./utils/users');

const app = express();
const server = http.createServer(app);
const io=socketio(server);

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

const botName = 'bot';

io.on('connection', socket => {
    socket.on('joinRoom', ({username, room}) => {
        const user = userJoin(socket.id, username, room);
        socket.join(user.room);
        socket.emit('message', formatMessage(botName, 'welcome'));
        socket.broadcast.to(user.room).emit('message', formatMessage(botName, `new user ${user.username}`));
        io.to(user.room).emit('roomUsers', {
            room: user.room,
            users: getRoomUsers(user.room)
        });
    });
    socket.on('chatMessage', msg => {
        const user = getCurrentUser(socket.id);
        io.to(user.room).emit('message', formatMessage(user.username, msg));
    });
    socket.on('disconnect', () => {
        const user = userLeaves(socket.id);
        if(user){
            io.to(user.room).emit('message', formatMessage(botName, `user left ${user.username}`));
            io.to(user.room).emit('roomUsers', {
                room: user.room,
                users: getRoomUsers(user.room)
            });
        }
    });
});

const PORT = 3000 || process.env.PORT;

server.listen(PORT, () => console.log(`server is running on port ${PORT}`));