route-splitting

routes.js

<Route
  name="landing"
  path="/"
  getComponent={
    (_, cb) => import('./views/LandingPage/LandingPage' /* webpackChunkName: 'landing' */)
      .then((module) => cb(null, module.default))
      .catch((error) => cb(error, null))
  }
</Route>

webpack.js

//extract css from all the split chunks into main.hash.css
new ExtractTextPlugin({
  filename: 'css/[name].[contenthash:8].css',
  allChunks: true, 
}),