server.js

require('dotenv').config();
// Require dependencies
const express = require("express");
const session = require("express-session");
// const cookieSession = require("cookie-session");

// Require models for syncing 
const db = require("./models");;

// Require configured passport file 
const passport = require("./config/passport");

// Set up PORT 
const PORT = process.env.PORT || 3001;

// Create Express app 
const app = express();

// CORS for sending front-end API to back-end server across urls
app.use(function(req, res, next) {
  res.header('Access-Control-Allow-Credentials', true);
  res.header('Access-Control-Allow-Origin', req.headers.origin);
  res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
  res.header('Access-Control-Allow-Headers', 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept');
  if ('OPTIONS' == req.method) {
    res.sendStatus(200);
  } else {
    next();
  }
});

// const cors = require('cors');
// app.use(cors());

// Express set-up 
app.use(express.urlencoded({ extended: true }));
app.use(express.json());

// Serve up static assets (on Heroku)
if (process.env.NODE_ENV === "production") {
  app.use(express.static("client/build"));
}

// Set up sessions to keep track of user's login status
app.use(
  session({ secret: process.env.SESSION_SECRET, resave: false, saveUninitialized: false })
);

// Use passport middleware 
app.use(passport.initialize());
app.use(passport.session());

// API Routes
const routes = require("./routes");
app.use(routes);

// Send every other request to the React app
const path = require("path")
app.get("*", (req, res) => {
  res.sendFile(path.join(__dirname, "./client/build/index.html"));
});

// Sync database and log message upon success 
db.sequelize.sync().then(() => {
  app.listen(PORT, () => {
    console.log(`🌎 ==> API server now on port ${PORT}!`);
  });
});