React Routing をマスターする: アプリケーションをナビゲートするための完全ガイド

1. Introduction to React Router

React Router is a library for handling routing in React applications. It allows your app to navigate between different components and views without a full-page reload, making the user experience seamless.

---

2. Basic Setup

Start by installing react-router-dom:

npm install react-router-dom

Set up basic routing using BrowserRouter, Routes, and Route:

import React from 'react';
import { BrowserRouter as Router, Routes, Route, Link } from 'react-router-dom';

const Home = () => <h2>Home</h2>;
const About = () => <h2>About</h2>;

const App = () => {
  return (
    <Router>
      <nav>
        <Link to="/">Home</Link>
        <Link to="/about">About</Link>
      </nav>

      <Routes>
        <Route path="/" element={<Home />} />
        <Route path="/about" element={<About />} />
      </Routes>
    </Router>
  );
};

export default App;

---

3. Nested Routing

For more complex apps, you can nest routes. Here’s how to set up nested routes in a parent component:

import React from 'react';
import { BrowserRouter as Router, Routes, Route, Link } from 'react-router-dom';

const Dashboard = () => <h2>Dashboard Home</h2>;
const Profile = () => <h2>Your Profile</h2>;

const DashboardLayout = () => {
  return (
    <div>
      <nav>
        <Link to="/dashboard">Home</Link>
        <Link to="/dashboard/profile">Profile</Link>
      </nav>
      <Routes>
        <Route path="/" element={<Dashboard />} />
        <Route path="profile" element={<Profile />} />
      </Routes>
    </div>
  );
};

const App = () => {
  return (
    <Router>
      <Routes>
        <Route path="/dashboard/*" element={<DashboardLayout />} />
      </Routes>
    </Router>
  );
};

export default App;

---

4. Dynamic Routing

Dynamic routing allows you to pass parameters in the URL. Here’s how to define and access a dynamic route:

import { useParams } from 'react-router-dom';

const User = () => {
  const { id } = useParams();
  return <h2>User ID: {id}</h2>;
};

const App = () => {
  return (
    <Router>
      <nav>
        <Link to="/user/1">User 1</Link>
        <Link to="/user/2">User 2</Link>
      </nav>

      <Routes>
        <Route path="/user/:id" element={<User />} />
      </Routes>
    </Router>
  );
};

export default App;

---

5. Protected Routes

To implement protected routes, you can create a custom PrivateRoute component:

import { Navigate, Outlet } from 'react-router-dom';

const useAuth = () => {
  const user = { loggedIn: true }; // Replace with actual auth logic
  return user && user.loggedIn;
};

const PrivateRoute = () => {
  const isAuth = useAuth();
  return isAuth ? <Outlet /> : <Navigate to="/login" />;
};

const App = () => {
  return (
    <Router>
      <Routes>
        <Route path="/login" element={<Login />} />
        <Route path="/dashboard" element={<PrivateRoute />}>
          <Route path="" element={<Dashboard />} />
        </Route>
      </Routes>
    </Router>
  );
};

export default App;

---

6. Programmatic Navigation

Sometimes, you may want to navigate programmatically, like after a form submission. Use the useNavigate hook in React Router v6:

import { useNavigate } from 'react-router-dom';

const Login = () => {
  const navigate = useNavigate();

  const handleLogin = () => {
    // Login logic here...
    navigate('/dashboard');
  };

  return (
    <div>
      <h2>Login</h2>
      <button onClick={handleLogin}>Login</button>
    </div>
  );
};

export default Login;

---

7. 404 Pages

Handle 404 (Not Found) errors by creating a catch-all route:

const NotFound = () => <h2>404 - Page Not Found</h2>;

const App = () => {
  return (
    <Router>
      <Routes>
        <Route path="/" element={<Home />} />
        <Route path="/about" element={<About />} />
        <Route path="*" element={<NotFound />} />
      </Routes>
    </Router>
  );
};

export default App;

---

8. Performance Considerations

For large applications, lazy loading routes can improve performance. Here’s how to implement lazy loading with React.lazy() and Suspense:

import React, { Suspense, lazy } from 'react';
import { BrowserRouter as Router, Routes, Route } from 'react-router-dom';

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

const App = () => {
  return (
    <Router>
      <Suspense fallback={<div>Loading...</div>}>
        <Routes>
          <Route path="/" element={<Home />} />
          <Route path="/about" element={<About />} />
        </Routes>
      </Suspense>
    </Router>
  );
};

export default App;

---

以上がReact Routing をマスターする: アプリケーションをナビゲートするための完全ガイドの詳細内容です。詳細については、PHP 中国語 Web サイトの他の関連記事を参照してください。