server.js

const path = require('path');
const express = require('express');
const http = require('http');
const socketio = require('socket.io');

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

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

//Run when a client connects
io.on('connection', socket => {
    console.log('New websocket connection');

    socket.emit('message', 'Welcome to GradAssist');

    //Brodcast when a user connects
    socket.emit('message', 'A user has joined the chat');

    //Runs when client disconnects
    socket.on('disconnect', ()=> {
        io.emit('message', 'A user has left the chat')
    });

    //Listen for chatMessage
    socket.on('chatMessage', () => {
        io.emit('message', msg);
    })
});

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

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