@welldone-software/env-config

Overview

Have your configuration in one place, organized in a js native structure, possbily hirarchial, but still easily configurable and overideable by environment variables, as recommended by the Twelve-Factor App methodology

{
  port: 1234,
  db: {
    hostName: 'example.com',
    port: 4321,
  },
  friends: ['Adam', 'Rachel'],
  isCors: true
}

This Small and powerfull config library reada keys from the config object and searches proccess.env for corresponding keys according to a naming convension.

This allows your apps to use config objects that fully support literal objects, literal arrays, numbers, strings and booleans , while stil being configured/overidden by env vars.

Conventions

• JS config object is literal javascript object with camalCase members.
• The environment variables are expected in UPPER_SNAKE_CASE convention.
• Two underscores (__) mean nesting, e.g. DB_SETTINGS__CONNECTION_STRING translated to dbSettings.connectionString
• Supports String, Boolean, Number and Array values.
• Types are determined by defaults in config file.

Usage

Environment variables (specified in .env file)

DB__HOST_NAME=mydomain.com
DB__PORT=3060
DB__USER=ADMIN
DB__PASSWORD=ygIYDG*&h8&ADSGH
IS_CORS=false
ANOTHER_KEY=anothervalue
FRIENDS__1=Sara

config.js

const mapEnv = require('@welldone-software/env-config')

module.exports = mapEnv({
  port: 1234,
  db: {
    hostName: 'example.com',
    port: 4321,
    user: '',
    password: '',
  },
  friends: ['Adam', 'Rachel'],
  isCors: true
})

result

{
  port: 1234,
  db: {
    hostName: 'mydomain.com',
    port: 3060,
    user: 'ADMIN',
    password: 'ygIYDG*&h8&ADSGH',
  },
  friends: ['Adam', 'Sara'],
  isCors: false
}

Advantages

• Single source of truth - one place to define all posibble config keys.
• Simple to use but still allows for rather complex configurations: not just strings and not just flat structures.
• Uses 'native' naming convention in each environment so configs look natural both in JS and in ENV.
• Much more readable than the alternative: const port = proccess.env.PORT || 1000

Roadmap

• Add typing support (typescript and Flow)