Example for webpack

gistfile1.txt

const settings = (mode === 'production') ? JSON.stringify(require('./src/config/settings.prod.json')) : JSON.stringify(require('./src/config/settings.dev.json'));

module.exports = {
  context: path.resolve('./src'),
  entry: {
    vendor: ['react', 'pouchdb', 'redux', 'whatwg-fetch'],
    demo_app: './init.tsx'
  },
  output: {
    path: path.resolve('./dist'),
    filename: 'static/js/[name].bundle.js'
  },
  externals: {
    settings: settings
  },
  .....
  
  That's how our settings.dev.json looks like.
  {
  "remoteCouchUrl": "http://localhost:5984/",
  "apiBaseUrl": "http://localhost:3000"
  }
  and in settings.prod.json you can production values.
  
  This is how we import them.
  import * as settings from 'settings'; (It's typescript syntax as we are using react with typescript.)