server.js

const path = require('path');
const express = require('express');
const mongoose = require('mongoose');
const dotenv = require('dotenv').config();
const logger = require('morgan');

const config = require('./config'); // configuration
const routes = require('./routes'); //  routing

const PORT = process.env.PORT || config.port; // defining port number

exports.bootstrap = async () => {
  await dbInit();

  const app = express(); //creating express app

  app.disable('etag'); // disable etag

  app.disable('x-powered-by'); // disable x-powered-by

  app.use(express.json(config.json)); // configuration for MIME type

  app.use(logger('dev')); // for logging the routes

  if (dotenv.error) throw dotenv.error; // for dotenv
  console.info(`key added in env by dotenv are:\n`, dotenv.parsed);

  app.use(express.static(path.join(__dirname, 'public'), config.static)); // public directory setup

  /* *********************** set up  for routes *********************** */
  app.use('/', routes);

  app.listen(PORT, () => console.log(`Listening on ${PORT}`)); // listening port number
};

/**
 * dbInit
 */
async function dbInit() {
  console.info('init db connection.');
  await mongoose.connect(config.mongoURI, {
    useNewUrlParser: true,
    uri_decode_auth: true,
  });
  // Get the default connection
  const db = mongoose.connection;

  //Bind connection to error event (to get notification of connection statusCode)
  db.on('error', console.error.bind(console, 'MongoDB connection error:'));
}