Sample of Pinterest Mweb code splitting

sample-codesplitting.js

// Create a loader
const Closeup = () => import(/* webpackChunkName: "CloseupPage" */ 'app/mobile/routes/CloseupPage');

// Register it to the route
route('/pin/:pinId', routes.Closeup, { name: 'Closeup' }),

// Render a react-router-v4 Route with the route bundle loader
<Route exact key="matched-route" path={path} render={matchProps =>
  <PageRoute
    bundleLoader={loader}
    routeName={name}
    {...matchProps}
    {...props}
  />}
/>

// Async load the route bundle
class PageRoute extends PureComponent {
  render() {
    const { bundleLoader, ...props } = this.props;
    return <Loader loader={bundleLoader} {...props} />;
  }
}

// Load it and render
class Loader extends PureComponent {
  componentWillMount() {
    this.props.loader().then(module => {
      this.setState({ LoadedComponent: module.default });
    });
  }
}