server.js

// require is a node js keyword like "import" in typescript

// express library, create running server. can listen to incoming request
const express = require('express'); 
// app is a instance of express library. We are going to use it to be able to create server and be able to respond http request coming from browser/client side.
const app = express();
// Library used to be able to parse incoming data. Client is going to send us JSON data. body-parse helps us to parse the data from the body. It knows how to parse images, file, etc.
const bodyParser = require('body-parser');
// http library allows us to create http servers
const http = require('http');
const path = require('path');

const cookieParser = require('cookie-parser');
const session = require('express-session');

app.use(cookieParser());

if(process.env.SESSION_SECRET) {
        app.use(session({
                secret: process.env.SESSION_SECRET,
                resave: true,
                saveUninitialized: true }));

} else {
        app.use(session({
                secret: 'test',
                resave: true,
                saveUninitialized: true}));

}



var passport = require('passport');

app.use(passport.initialize());
app.use(passport.session());

// Initialize bodyparser. We are turn on the feature to parse json data.
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
// Point static path to dist -- For building -- REMOVE
app.use(express.static(path.join(__dirname, 'dist')));

// CORS - Cross-Origin Resource Sharing
// For security purposes, browser only allowed client side to request data from its own server. CORS is a mechanism that determines whether to block or fulfill requests for restricted resources on a web page from another domain outside the domain from which the resource originated.
app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "http://localhost:4200");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  res.header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");
  res.header("Access-Control-Allow-Credentials", "true");
  next();
});

const port = process.env.PORT || '3100';
app.set('port', port);

// Create HTTP server
const server = http.createServer(app);


require('./server/app')(app);

// For Build: Catch all other routes and return the index file -- BUILDING
app.get('*', function (req, res) {
  res.sendFile(path.join(__dirname, 'dist/index.html'));
});

// server.listen(port);
server.listen( port , function() {console.log('Running on ' + app.get('port'));});