react 之 lazyLoad```js import React,{ lazy, Suspense } from

import React,{ lazy, Suspense } from 'react';

// 需要懒加载的组件

const Home = lazy(() => import('./home'));

const About = lazy(() => import('./about'));

//  注册路由的地方  fallback 网络较慢时感知正在加载

<Suspense fallback={<h1>loading ....加载中</h1>} >

  <Route path='./about' component={Home}></Route>

  <Route path='./home' component={About}></Route>

</Suspense>