Environment Based Config

config.js

const SOME_KEY = 'someOption'

const something = {
  development: {
    [SOME_KEY]: 'for dev'
  },
  production: {
    [SOME_KEY]: 'for prod'
  },
  test: {
    [SOME_KEY]: 'for test'
  }
}

module.exports = something[process.env.NODE_ENV]

// Usage: import { someOption } from 'config.js'

Each React package in a monorepo could have its own .env.* file that uses REACT_APP_ variables, but dependency env variables are overwritten when the dependency is imported. See more here: facebook/create-react-app#4654

Instead, a different set of variables will be provided based on the NODE_ENV. This also helps align multiple packages that connect to the same service while reducing the number of ENV files.