code-splitting-1.js

import React, { PureComponent, Suspense, lazy, Fragment } from 'react';
import { Route, Switch, HashRouter } from 'react-router-dom';
import Loading from 'components/UI/Loading';

const LoginScene = lazy(() => import('Scenes/auth/LoginScene'));
const ProfileScene = lazy(() => import('Scenes/user/ProfileScene'));

import {
  loginRoute,
  profileRoute
} from './routes';

class App extends PureComponent {
  render() {
    return (
      <HashRouter>
        <Suspense fallback={<Loading />}>
          <Fragment>
            <Switch>
              <Route
                path={loginRoute()}
                component={<LoginScene />}
              />
              <Route
                path={userProfileRoute()}
                component={<Profile />}
              />
            </Switch>
          </Fragment>
        </Suspense>
      </HashRouter>
    );
  }
}