Authenticated.js

import React, { PropTypes } from 'react';
import { connect } from 'react-redux';

const Authenticated = React.createClass({
  propTypes: {
    children: PropTypes.element.isRequired,
    isAuthenticated: PropTypes.bool.isRequired,
    history: PropTypes.object.isRequired,
  },
  componentDidMount() {
    this.checkAuth(this.props);
  },
  componentWillReceiveProps(nextProps) {
    this.checkAuth(nextProps);
  },
  checkAuth(props) {
    if (!props.isAuthenticated) {
      this.props.history.replaceState(null, '/login');
    }
  },
  render() {
    return this.props.isAuthenticated ? this.props.children : null;
  },
});

export default connect(
  ({ sessionToken }) => ({ isAuthenticated: !!sessionToken })
)(Authenticated);

routes.js

<Route path="/" component={App}>
  <Route component={Authenticated}>
      <IndexRoute component={Home} />
  </Route>
  <Route component={UnAuthenticated}>
    <Route path="/login" component={Login} />
  </Route>
</Route>

UnAuthenticated.js

import React, { PropTypes } from 'react';
import { connect } from 'react-redux';

const UnAuthenticated = React.createClass({
  propTypes: {
    children: PropTypes.element.isRequired,
    isAuthenticated: PropTypes.bool.isRequired,
    history: PropTypes.object.isRequired,
  },
  componentDidMount() {
    this.checkAuth(this.props);
  },
  componentWillReceiveProps(nextProps) {
    this.checkAuth(nextProps);
  },
  checkAuth(props) {
    if (props.isAuthenticated) {
      this.props.history.replaceState(null, '/');
    }
  },
  render() {
    return !this.props.isAuthenticated ? this.props.children : null;
  },
});

export default connect(
  ({ sessionToken }) => ({ isAuthenticated: !!sessionToken })
)(UnAuthenticated);