Lazy loading via React Loadable for routing

routes.js

import Loadable from 'react-loadable';

const A = Loadable({
  loader: () => import('../A' /* webpackChunkName: "pc-r-A" */),
  loading: () => null,
});

const B = Loadable({
  loader: () => import('../B' /* webpackChunkName: "pc-r-B" */),
  loading: () => null,
});

const routes = [{
  route: '/',
  regions: {
    side: A,
    main: B,
  },
}];