这里展示了React-Router v6中最基本的身份验证实现。PrivateRoutes中的loggedIn标志在更新上下文后更新为true时不会改变，因此在导航到它们时无法访问私有路由。为什么会这样？

import './App.css';
import {
  BrowserRouter,
  Navigate,
  Outlet,
  Route,
  Routes,
  useNavigate
} from 'react-router-dom';
import React, { useState } from 'react';

function App() {
  return (
    <div>
      <AuthProvider>
        <BrowserRouter>
          <Routes>
            <Route path="/" element={<HomePage />} />

            <Route element={<PrivateRoutes />}>
              <Route path="/secret" element={<SecretPage />} />
              {/** ... Other protected pages ...*/}
            </Route>
            
          </Routes>
        </BrowserRouter>
      </AuthProvider>
    </div>
  );
}

function PrivateRoutes() {
  const { loggedIn } = useAuth();

  return loggedIn ? <Outlet />: <Navigate to="/" />
}

function HomePage() {
  const navigate = useNavigate();

  return <>
    <h1>Home page</h1>
    <button onClick={() => navigate('/secret')}>
      Go to secret page
    </button>
  </>
}

function SecretPage() {
  return <>
    <h1>Secret Page</h1>
  </>
}

const AuthContext = React.createContext()

const AuthProvider = ({ children }) => {
  const { loggedIn, signIn } = useAuth()

  return
    <AuthContext.Provider value={loggedIn}>
      
      {/** 
       * Button to trigger sign in and showing the
       * current status.
      */}
      <button onClick={signIn}>LogIn</button>
      <h2>Logged In: {loggedIn.toString()}</h2>
      <p>-----------------------</p>

      {children}
    </AuthContext.Provider>
}

const useAuth = () => {
  const [loggedIn, setLoggedIn] = useState(false)

  const signIn = () => {

    {/** sign in logic ....*/}

    setLoggedIn(true);
  };

  return { loggedIn, signIn };
}

export default App;