server.js

const express = require('express')
const app = express()
const mongoose = require('mongoose');
require('dotenv').config()
const uri = process.env.MONGODB_URI;
mongoose.connect(uri, {useNewUrlParser: true, useUnifiedTopology: true}).then(res => console.log("Connected to DB"))
.catch(err => console.log(err))

var bodyParser = require('body-parser')
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())

app.use(function (req, res, next) {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Headers',
      'Content-Type, X-Requested-With, Origin');
  res.header('Access-Control-Allow-Methods',
      'GET, POST, PUT, PATCH, DELETE, OPTIONS');
  res.header("Access-Control-Allow-Credentials", "true");
  next();
});


require('./controllers/quizzes-controller')(app)
require('./controllers/questions-controller')(app)
require('./controllers/quiz-attempts-controller')(app)

app.listen(process.env.PORT||4000)