index.js

const mongoose = require('mongoose');
require('dotenv').config({ path: './config.env' });

process.on('uncaughtException', (err) => {
  console.log('UNCAUGHT EXCEPTION! 💥 Shutting down...');
  console.log(err);
  process.exit(1);
});

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

mongoose
  .connect(process.env.DATABASE, {
    autoIndex: true,
    useNewUrlParser: true,
    useCreateIndex: true,
    useFindAndModify: false,
    useUnifiedTopology: true,
  })
  .then(() => {
    console.log('DB Connection Successful');
  })
  .catch((err) => {
    console.log(err);
  });

const port = process.env.PORT || 3000;
const server = app.listen(port, () => {
  console.log(`App running on port ${port}`);
});

process.on('unhandledRejection', (err) => {
  console.log('UNHANDLED REJECTION! 💥 Shutting down...');
  console.log(err.message);
  server.close(() => {
    process.exit(1);
  });
});

// HEROKU //
process.on('SIGTERM', () => {
  console.log('SIGTERM RECEIVED. Shuting down peacefully');
  server.close(() => {
    console.log('Process terminated');
  });
});