Redux state passed to onEnter of react-router.

app.js

import createHistory from 'history/lib/createBrowserHistory';
import createStore   from './redux/createStore';
import createRoutes  from './routes';
import React         from 'react';
import { Provider }  from 'react-redux';
import { Router }    from 'react-router';
import { render }    from 'react-dom';

const history = createHistory();
const store = createStore(history, window.__data);

render((
  <Provider store={store}>
    <Router history={history}>
      {createRoutes(store)}
    </Router>
  </Provider>
), document.getElementById('root'));

createRequireAuth.js

export default store =>
  ( nextState, replaceState ) => {
    if ( !store.getState().auth.user ) {
      replaceState({ nextPathname: nextState.location.pathname }, '/');
    }
  };

routes.jsx

import AppContainer         from '../containers/AppContainer';
import createRequireAuth    from './createRequireAuth';
import DashboardContainer   from '../containers/DashboardContainer';
import HomeContainer        from '../containers/HomeContainer';
import React                from 'react';
import { Redirect, Route }  from 'react-router';

export default store => (
  <Route component={AppContainer}>
    <Route path="/" component={HomeContainer} />
    <Route onEnter={createRequireAuth(store)}>
      <Route path="dashboard" component={DashboardContainer} />
    </Route>
  </Route>
);