server.js

const express = require('express');
const bodyParser = require('body-parser');
const path = require('path');
const http = require('http');
const app = express();
// Add headers
app.use(function (req, res, next) {

    res.setHeader('Content-Type', 'application/json');
    // Website you wish to allow to connect
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Allow-Control-Allow-Origin', '*');
    // Request methods you wish to allow
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
    
    // Request headers you wish to allow
    res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
    res.setHeader('Allow-Control-Allow-Headers', '*');
    // Set to true if you need the website to include cookies in the requests sent
    // to the API (e.g. in case you use sessions)
    res.setHeader('Access-Control-Allow-Credentials', true);
    res.setHeader("Access-Control-Expose-Headers", "Access-Control-*");
    res.setHeader("Access-Control-Allow-Headers", "Access-Control-*, Origin, X-Requested-With, Content-Type, Accept")
    res.setHeader('Allow', 'GET, POST, PUT, DELETE, OPTIONS, HEAD');
    // Pass to next layer of middleware
    next();
    });
// API file for interacting with MongoDB
const api = require('./server/routes/api');

// Parsers
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false}));

// Angular DIST output folder
app.use(express.static(path.join(__dirname, 'dist')));

// API location
app.use('/api', api);

// Send all other requests to the Angular app
app.get('*', (req, res) => {
    res.sendFile(path.join(__dirname, 'dist/index.html'));
});

//Set Port
const port = process.env.PORT || '3000';
app.set('port', port);

const server = http.createServer(app);

server.listen(port, () => console.log(`Running on localhost:${port}`));