React Router Dom – Guided Study Workspace

1. What Is Routing & Client-Side Routing?

In traditional multi-page websites, every link click triggers an HTTP request to the web server, which sends back an entirely new HTML document—causing the entire browser screen to blink and reload.

In a React Single-Page Application (SPA), Client-Side Routing intercepts browser URL changes using the HTML5 History API (pushState) and dynamically mounts the corresponding React component—without requesting a new HTML page!

🚀 The Benefit: Instant screen transitions, preserved global application state, reduced bandwidth usage, and a seamless native-app feel.

3. Setting Up React Router DOM

Install the official package from npm:

npm install react-router-dom

Wrap your root application with <BrowserRouter> and define routes inside <Routes>:

import { BrowserRouter, Routes, Route } from 'react-router-dom';
import { Home } from './pages/Home';
import { About } from './pages/About';

export function App() {
  return (
    <BrowserRouter>
      <Routes>
        <Route path="/" element={<Home />} />
        <Route path="/about" element={<About />} />
      </Routes>
    </BrowserRouter>
  );
}

5. Navigation: Link, NavLink & useNavigate

Tool	Usage	Primary Purpose
`<Link to="/path">`	Declarative in JSX	Client-side link navigation without browser reload
`<NavLink to="/path">`	Active-styled navigation	Provides `isActive` boolean to highlight current tab
`useNavigate()`	Programmatic in functions	Imperative redirect after login, submit, or timer

import { Link, NavLink, useNavigate } from 'react-router-dom';

export function Navbar() {
  const navigate = useNavigate();

  return (
    <nav>
      <NavLink to="/" className={({ isActive }) => isActive ? 'active' : ''}>Home</NavLink>
      <Link to="/about">About</Link>
      <button onClick={() => navigate('/dashboard')}>Go to Dashboard</button>
    </nav>
  );
}

6. Route Parameters & useParams

Use a colon : to define dynamic parameters in your route path. In the target component, read the values using useParams():

// App.jsx
<Route path="/products/:productId" element={<ProductDetail />} />

// ProductDetail.jsx
import { useParams } from 'react-router-dom';

export function ProductDetail() {
const { productId } = useParams();
return <h2>Showing details for product #{productId}</h2>;
}

7. Nested Routes, Layouts & <Outlet />

Nested routing allows child components to share a parent layout (e.g. persistent sidebar, navigation bar) without re-mounting the layout on page change:

// App.jsx
<Route path="/dashboard" element={<DashboardLayout />}>
  <Route index element={<DashboardOverview />} />
  <Route path="settings" element={<Settings />} />
  <Route path="profile" element={<Profile />} />
</Route>

// DashboardLayout.jsx
import { Outlet, Link } from 'react-router-dom';

export function DashboardLayout() {
  return (
    <div className="dashboard">
      <aside>
        <Link to="/dashboard">Overview</Link>
        <Link to="/dashboard/settings">Settings</Link>
      </aside>
      <main>
        <Outlet />
      </main>
    </div>
  );
}

9. Handling 404 Fallback Pages

Use the wildcard path="*" at the bottom of your route definitions to capture any URL that does not match predefined rules:

10. Query Parameters with useSearchParams

Query strings like /courses?category=react&sort=asc are read and modified using useSearchParams():

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

export function CourseFilter() {
  const [searchParams, setSearchParams] = useSearchParams();
  const category = searchParams.get("category") || "all";

  return (
    <button onClick={() => setSearchParams({ category: "react" })}>
      Filter React (Current: {category})
    </button>
  );
}

12. Protected Routes (Authentication Guards)

Guard private pages (like dashboards or admin consoles) from unauthenticated users:

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

export function ProtectedRoute({ isAuthenticated }) {
  if (!isAuthenticated) {
    return <Navigate to="/login" replace />;
  }
  return <Outlet />;
}

14. Common Mistakes & Best Practices

Using <a href> instead of <Link to>: Causes full page reloads and state resets.
Forgetting <Outlet /> in nested layouts: Child components will fail to display.
Leading slash in nested child paths: Child routes under /dashboard should be defined as path="settings" (relative), not path="/settings".
Organize route trees hierarchically: Group related routes under shared layouts.

React Routing: React Router DOM, Dynamic Routes & Layouts