Mastering Next.js 13 App Router: A Complete Guide
Next.js 13 introduced a revolutionary App Router that changes how we think about routing in React applications. This new approach brings improved developer experience, better performance, and more intuitive file-based routing.
What’s New in App Router?
The App Router introduces several key concepts:
- File-based routing: Routes are defined by folder structure
- Layout system: Shared UI components across routes
- Server Components: Components that render on the server by default
- Streaming: Progressive page loading for better UX
Key Features
Layouts
Layouts allow you to share UI between routes:
// app/layout.tsx
export default function RootLayout({ children }: { children: React.ReactNode }) {
return (
<html>
<body>
<nav>Navigation</nav>
{children}
<footer>Footer</footer>
</body>
</html>
);
}Dynamic Routes
Create dynamic routes using square brackets:
// app/blog/[slug]/page.tsx
export default function BlogPost({ params }: { params: { slug: string } }) {
return <h1>Post: {params.slug}</h1>;
}Loading States
Create loading states with loading.tsx:
// app/blog/loading.tsx
export default function Loading() {
return <div>Loading posts...</div>;
}Migration Tips
Migrating from the Pages Router to App Router requires careful planning:
- Start with new routes in the App Router
- Gradually migrate existing pages
- Update data fetching patterns
- Test thoroughly
Conclusion
The App Router represents the future of Next.js development. Its improved developer experience and performance benefits make it an excellent choice for new projects.