server.js

const express = require("express");
const mongoose = require("mongoose");
const routes = require("./routes");
const app = express();
const PORT = process.env.PORT || 3001;
var http = require("http").Server(app);
const io = require("socket.io")(http);

// Define middleware here
app.use(express.urlencoded({ extended: true }));
app.use(express.json());
// Serve up static assets (usually on heroku)
if (process.env.NODE_ENV === "production") {
  app.use(express.static("client/build"));
}

// Define API routes here
app.use(routes);

// Connect to MongoDB
mongoose.connect(process.env.MONGODB_URI || 'mongodb://localhost/Google-Books', { useNewUrlParser: true });

//Connect to socket io
io.on('connection', function(socket){
  console.log("User connected");
  socket.on('message', function(msg){
    io.emit('message', msg);
  });
});

app.listen(PORT, function() {
  console.log(`🌎 ==> API server now on port ${PORT}!`);
});