这篇文章将通过一个demo来描述，怎么在使用typeScript的项目里面，使用react-router和React.lazy来实现lazy loading来提升网页性能。
建议先读一下相关的React官方文档：https://reactjs.org/docs/code-splitting.html#suspense

首先这个demo共有4个页面，3个url
1 '/' -> Home Page
2 '/blogList' ->Blog List Page
3 '/blogDetails/:id' -> Blog Details Page

大家都知道对于Blog Details Page的页面，通常的做法是在url里面加变量，以此来区分，当前是哪篇博客。
在这个例子里，我们创建了2篇博客，所以页面总共算起来有4个，但是在代码去实现的时候，我们会有3个文件：HomePage.tsx, BlogDetailsPage.tsx, BlogDetailsPage.tsx.

下面是我们的4个页面，从这个页面上，就能看出来我们的user journey:

1：到了home page, 此上有个链接可以去到 blog list page
2： 到了blog list page, 从页面上有2篇博客链接
3：点击第一篇博客链接，进入第一篇博客的详情页面
4： 点击第二篇博客链接，进入第二篇博客的详情页面

Home Page

Blog Lis tPage

第一篇Blog Details Page

第二篇Blog Details Page

安装react-router-dom && @types/react-router-dom

yarn add react-router-dom @types/react-router-dom 

配置react-router

index.tsx

// index.tsx
import React from "react";
import ReactDOM from "react-dom";
import { BrowserRouter } from "react-router-dom";
import "./index.scss";
import App from "./App";
import * as serviceWorker from "./serviceWorker";

ReactDOM.render(
    <BrowserRouter>
        <App/>
    </BrowserRouter>
    , document.getElementById("root"));

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://bit.ly/CRA-PWA
serviceWorker.unregister();

App.tsx

//App.tsx
import React, { Suspense, lazy } from "react";
import { Switch, Route } from "react-router-dom";
import HomePage from './pages/HomePage/HomePage'
const BlogListPage = lazy(()=> import('./pages/blogListPage/BlogListPage'));
const BlogDetailsPage = lazy(()=> import('./pages/blogDetailsPage/BlogDetailsPage'));

function WaitingComponent(Component: React.FC<any> ) {
    return (props: any) => (
        <Suspense fallback={<div>Loading...</div>}>
            <Component {...props} />
        </Suspense>
    );
}

function App() {
    return (
        <Switch>
            <Route path="/blogList" component={WaitingComponent(BlogListPage)} />
            <Route path="/blogDetails/:id" component={WaitingComponent(BlogDetailsPage)} />
            <Route path="/" exact component={HomePage} />
        </Switch>
    );
}

export default App;

HomePage.tsx

//HomePage.tsx
import React from "react";
import logo from "./images/logo.svg";
import pink from "./images/pink.png";
import "./HomePage.scss";
import {Link} from "react-router-dom";

function App() {
    return (
        <div className="App">
            <header className="App-header">
                <img src={logo} className="App-logo" alt="logo" />
                <img src={pink} className="" alt="pink" />
                <Link to="/blogList">Blog List Page</Link>
            </header>
        </div>
    );
}

export default App;

BlogListPage.tsx

// BlogListPage.tsx
import React from "react";
import {RouteComponentProps} from "react-router";
import {Link} from "react-router-dom";

function BlogListPage() {
    return (
        <div className="BlogListPage">
            <div>Blog List Page</div>
            <ul>
                <li>
                    <Link to="/blogDetails/1">First Blog</Link>
                </li>
                <li>
                    <Link to="/blogDetails/2">Second Blog</Link>
                </li>
            </ul>

        </div>
    );
}

export default BlogListPage;

BlogDetailsPage.tsx

//BlogDetailsPage.tsx
import React from "react";
import {RouteComponentProps, useParams} from 'react-router-dom'

type routerParams = {id: string}

function BlogDetailsPage(props: RouteComponentProps<routerParams>){
    const {id} = useParams();
    return (
        <div className="BlogDetailsPage">
            <div>Blog Details page</div>
            <p>The id in the url is: {id}</p>
        </div>
    );
}
export default BlogDetailsPage;