auth.js

// Borrowed from react-router exmample "Auth Flow"
// https://github.com/ReactTraining/react-router/tree/master/examples/auth-flow

render((
  <Router history={withExampleBasename(browserHistory, __dirname)}>
    <Route path="/" component={App}>
      <Route path="login" component={Login} />
      <Route path="logout" component={Logout} />
      <Route path="admin" onEnter={requireAuth}> // Route hook
        <Route path="about" component={About} onEnter={...} /> // Component hook
        <Route path="dashboard" component={Dashboard} />
      </Route>
    </Route>
  </Router>
), document.getElementById('example'))