What is the best practice to connect/disconnect to a database?

Question

I\'d like to know how to work with connectivity to a database in MEAN stack application. In particular, when should I create a connection to a database and when should I destroy

Answer 1

This is my solution :

import express from 'express';
import mongoose from 'mongoose';
import { name } from '../package.json';
import * as localconfig from './local-config';
import debug from 'debug';
debug(name);
const app = express();

const port = process.env.PORT || 3000;
const mongoUrl = localconfig.credentials.MONGO_URL;

import usersRoutes from './routes/users/user-routes';

app.use('/v1/users', usersRoutes);

mongoose.connect(mongoUrl)
    .then(() => {
        debug('DB connection successful');
        app.listen(port, '0.0.0.0', () => {
            debug(`Running on port ${port}`);
        });
    })
    .catch((err) => {
        debug(err);
    });

You should first check weather the connection is successful or not and only then listen to a certain port. This is my app.js file where all the routes are loaded, so you do not have to call the db connection in all your files. You have a single config file where all the config is done. Your router file user-routes.js will look something similar to this:

import express from 'express';

import User from '../models/user'
const router = express.Router();

router.get('/', (req, res, next) => {
    User.find()
        .then((response) => res.json(response))
        .catch((err) => next(err));
});

module.exports = router;