Use Joi to validate/assert your required environment
Usage:
var envok = require('envok');
var Joi = require('joi');
//Will make sure NODE_ENV is present...and any other Joi validation you use..
//Also will return an object with camelized keys for each key in the schema
const config = envok({
NODE_ENV: Joi.string().required().allow('development', 'staging', 'production'),
})
module.exports = config;