etc
The Twelve-Factor App
https://12factor.net/config
General
Process | Node.js v12.7.0 Documentation
https://nodejs.org/api/process.html#process_process_envNode.js Everywhere with Environment Variables!
https://medium.com/the-node-js-collection/making-your-node-js-work-everywhere-with-environment-variables-2da8cdf6e786