server.js

const mongoose = require('mongoose');
const dotenv = require('dotenv');
//-------------------Config----------------//
dotenv.config({ path: './config.env' });
//----------Exception Handling-------------//
process.on('uncaughtException', err => {
  console.log('UNCAUGHT EXCEPTION! 💥 Shutting down...');
  console.log(err.name, err.message);
  process.exit(1);
});
//--------------------DB-------------------//
const app = require('./app');

const DB = process.env.DATABASE.replace(
  '<password>',
  process.env.DATABASE_PASSWORD
);
mongoose
  .connect(DB, {
    useNewUrlParser: true,
    useCreateIndex: true,
    useFindAndModify: false,
    useUnifiedTopology: true
  })
  .then(console.log('DB connection successful!'));

//------------------Listener----------------//
const port = process.env.PORT || 8000;
const server = app.listen(port, () => {
  console.log(`Listening on port ${port} in the ${process.env.NODE_ENV} mode`);
});
//--------------Rejection Handler------------//
process.on('unhandledRejection', err => {
  console.log('UNHANDLED REJECTION! 💥 Shutting down...');
  console.log(err.name, err.message);
  server.close(() => {
    process.exit(1);
  });
});

process.on('SIGTERM', () => {
  console.log('👋 SIGTERM RECEIVED. Shutting down gracefully');
  server.close(() => {
    console.log('💥 Process terminated!');
  });
});