// Setup basic express server const express = require('express'); const app = express(); const path = require('path'); const server = require('http').createServer(app); const io = require('socket.io')(server); const port = process.env.PORT || 3000; server.listen(port, () => { console.log('Server listening at port %d', port); }); // Routing app.use(express.static(path.join(__dirname, 'public'))); // Chatroom let numUsers = 0; io.on('connection', (socket) => { let addedUser = false; // when the client emits 'new message', this listens and executes socket.on('new message', (data) => { // we tell the client to execute 'new message' socket.broadcast.emit('new message', { username: socket.username, message: data }); }); // when the client emits 'add user', this listens and executes socket.on('add user', (username) => { if (addedUser) return; // we store the username in the socket session for this client socket.username = username; ++numUsers; addedUser = true; socket.emit('login', { numUsers: numUsers }); // echo globally (all clients) that a person has connected socket.broadcast.emit('user joined', { username: socket.username, numUsers: numUsers }); }); // when the client emits 'typing', we broadcast it to others socket.on('typing', () => { socket.broadcast.emit('typing', { username: socket.username }); }); // when the client emits 'stop typing', we broadcast it to others socket.on('stop typing', () => { socket.broadcast.emit('stop typing', { username: socket.username }); }); // when the user disconnects.. perform this socket.on('disconnect', () => { if (addedUser) { --numUsers; // echo globally that this client has left socket.broadcast.emit('user left', { username: socket.username, numUsers: numUsers }); } }); });