React-router4 第六篇 No Match 404

https://reacttraining.com/react-router/web/example/no-match
react-router-dom 又一个新属性 Switch

在Switch 的包裹下， 如果不填写path属性，那么，所有未定义的路由都会渲染这个组件，顺便把路由传进去

import React from 'react'
import {
  BrowserRouter as Router,
  Route,
  Link,
  Switch,
  Redirect
} from 'react-router-dom'

const NoMatchExample = () => (
  <Router>
    <div>
      <ul>
        <li><Link to="/">Home</Link></li>
        <li><Link to="/old-match">Old Match, to be redirected</Link></li>
        <li><Link to="/will-match">Will Match</Link></li>
        <li><Link to="/will-not-match">Will Not Match</Link></li>
        <li><Link to="/also/will/not/match">Also Will Not Match</Link></li>
      </ul>
      <Switch>
        <Route path="/" exact component={Home}/>
        <Redirect from="/old-match" to="/will-match"/>
        <Route path="/will-match" component={WillMatch}/>
        <Route component={NoMatch}/>       // 所有没有定义的路由都会匹配NoMatch组件
      </Switch>
    </div>
  </Router>
)

const Home = () => (
  <p>
    A <code>&lt;Switch></code> renders the
    first child <code>&lt;Route></code> that
    matches. A <code>&lt;Route></code> with
    no <code>path</code> always matches.
  </p>
)

const WillMatch = () => <h3>Matched!</h3>

const NoMatch = ({ location }) => (
  <div>
    <h3>No match for <code>{location.pathname}</code></h3>
  </div>
)

export default NoMatchExample