Backend routing

In the Rendering to strings section, you implemented a single request handler in the server that responded to requests for the root URL (/). Your application is going to need to handle more than a single route. You learned how to use the react-router package for routing in Chapter 9, Handling Navigation with Routes, but now, you're going to see how to use the same package in Node.js.

First, let's take a look at the main App component:

import { Routes, Route, Link, Outlet } from 
  "react-router-dom";
 
import FirstHeader from "./first/FirstHeader";
import FirstContent from "./first/FirstContent";
import SecondHeader from "./second/SecondHeader";
import SecondContent from "./second/SecondContent";
 
function Layout() {
  return (
    <section>
      <Outlet />
    </section>
  );
}
 
export...