React中路由组件的lazyLoad

1.通过React的lazy函数配合import()函数动态加载路由组件 ===> 路由组件代码会被分开打包

    const Login = lazy(()=>import('@/pages/Login'))

2.通过<Suspense>指定在加载得到路由打包文件前显示一个自定义loading界面

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

        <Switch>

            <Route path="/xxx" component={Xxxx}/>

            <Redirect to="/login"/>

        </Switch>

    </Suspense>

举个例子

import React, { Component,lazy,Suspense} from 'react'
import {NavLink,Route} from 'react-router-dom'

// import Home from './Home'
// import About from './About'

import Loading from './Loading'
const Home = lazy(()=> import('./Home') )
const About = lazy(()=> import('./About'))

export default class Demo extends Component {
	render() {
		return (
			<div>
				<div className="row">
					<div className="col-xs-offset-2 col-xs-8">
						<div className="page-header"><h2>React Router Demo</h2></div>
					</div>
				</div>
				<div className="row">
					<div className="col-xs-2 col-xs-offset-2">
						<div className="list-group">
							{/* 在React中靠路由链接实现切换组件--编写路由链接 */}
							<NavLink className="list-group-item" to="/about">About</NavLink>
							<NavLink className="list-group-item" to="/home">Home</NavLink>
						</div>
					</div>
					<div className="col-xs-6">
						<div className="panel">
							<div className="panel-body">
								<Suspense fallback={<Loading/>}>
									{/* 注册路由 */}
									<Route path="/about" component={About}/>
									<Route path="/home" component={Home}/>
								</Suspense>
							</div>
						</div>
					</div>
				</div>
			</div>
		)
	}
}