Dotenv

.env file:
DB_HOST=localhost
DB_USER=root
DB_PASS=s1mpl3
require('dotenv').config();
const db = require('db');
db.connect({
  host: process.env.DB_HOST,
  username: process.env.DB_USER,
  password: process.env.DB_PASS
});
cross-env
{
  "scripts": {
    "start-prod": "cross-env NODE_ENV=production node ./app.js"
  }
}
debug
const debug = require('debug')('http')
  , http = require('http')
  , name = 'My App';
debug('booting %o', name);
http.createServer(function(req, res){
  debug(req.method + ' ' + req.url);
  res.end('hello\n');
}).listen(3000, function(){
  debug('listening');
});