setRouteLeaveHook路由钩子函数：处理路由切换时的操作

import React, { Component, PropTypes } from 'react';
import { Router, Route, hashHistory, Link } from 'react-router';

class Home extends Component {
  componentWillMount(){
    this.context.router.setRouteLeaveHook(
      this.props.route,
      this.routerWillLeave
    )
  }
  routerWillLeave( nextLocation ){
    return `页面即将从Home切换到${nextLocation.pathname}`
  }
  render(){
    return <div>
      <h1>Home</h1>
      <Links />
    </div>
  }
}

Home.contextTypes = {
  router: PropTypes.object.isRequired
};

const Contact = () => <div><h1>Contact</h1><Links /></div>;

const Links = () =>
  <nav>
    <Link to="/">Home</Link>
    <Link to="/contact">Contact</Link>
  </nav>

class App extends Component {
  render() {
    return (
      <Router history={hashHistory}>
        <Route path="/" component={Home} />
        <Route path="/contact" component={Contact} />
      </Router>
    );
  }
}

export default App;