index.js

Promise.all([
  import("react"),
  import("react-dom"),
  import("react-router"),
  import("react-router-redux"),
  import("source/store"),
  import("containers/Root"),
  import("source/index.css"),
  import("whatwg-fetch"),
  import("babel-polyfill"),
]).then(async ([
  React,
  { render },
  { browserHistory },
  { syncHistoryWithStore },
  { default: configureStore },
  { default: Root },
]) => {
  const target = document.getElementById("root");

  const store = configureStore();
  const history = syncHistoryWithStore(browserHistory, store);

  const mount = async Component => {
    const base = (<Component history={history} store={store} />);

    try {
      const { AppContainer } = await import("react-hot-loader");
      render(<AppContainer>{base}</AppContainer>, target);
    } catch (e) {
      render(base, target);
    }
  };

  mount(Root);

  if (module.hot) {
    module.hot.accept("source/containers/Root", async () => {
      const { default: NextRoot } = await import("containers/Root");
      mount(NextRoot);
    });
  }
});