server.js

const express = require('express');
const mongoose = require('mongoose');
const bodyParser = require('body-parser');
const passport = require('passport');
var cors = require('cors');
const path = require('path');

const users = require('./routes/api/users');
const profile = require('./routes/api/profile');
const posts = require('./routes/api/posts');

const app = express();

var corsOptions = {
  origin: '*',
  optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204
}

app.use(cors(corsOptions));

//Body parse middleware
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());

//DB config
const db = require('./config/keys').mongoURI;

//connect to mongodb
mongoose
	.connect(db, {useNewUrlParser: true})
	.then(() => console.log('MongoDb Connected'))
	.catch(error => console.log(`something's wrong`, error));

//Passport middleware
app.use(passport.initialize());

//Passport config
require('./config/passport.js')(passport);

//use Routes
app.use('/api/users', users);
app.use('/api/posts', posts);
app.use('/api/profile', profile);

//Serve static assets if in production
if(process.env.NODE_ENV === 'production'){
  //set a static folder
  app.use(express.static('client/build'));
  app.get('*', (req, res) => {
    res.sendFile(path.resolve(__dirname, 'client', 'build', 'index.html'));
  })
}

const port = process.env.PORT || 4000;

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