Dynamic Routing in Next.js

What You’ll Learn 📚

• Core concepts of dynamic routing in Next.js
• Key terminology and definitions
• Step-by-step examples from simple to complex
• Common questions and troubleshooting tips

Introduction to Dynamic Routing

In web development, dynamic routing allows you to create routes that are not predefined but generated based on data or user input. In Next.js, this is particularly powerful because it enables you to build pages that adapt to different parameters, like user IDs or product names, without having to manually create each page.

Think of dynamic routing like a customizable GPS. Instead of having a fixed path, it adjusts based on your destination!

Key Terminology

• Route: A path in your application that corresponds to a specific page.
• Dynamic Segment: Part of a route that can change, usually represented by a variable.
• Params: Parameters extracted from the dynamic segments of a route.

Simple Example: Dynamic User Profile

Let’s start with the simplest example: a dynamic user profile page. Imagine you have a social media app where each user has a profile page. Instead of creating a separate page for each user, you can use dynamic routing.

// pages/users/[id].js
import { useRouter } from 'next/router';

function UserProfile() {
  const router = useRouter();
  const { id } = router.query;

  return 
User Profile for ID: {id}
;
}

export default UserProfile;

Progressively Complex Examples

Example 1: Dynamic Product Page

// pages/products/[productId].js
import { useRouter } from 'next/router';

function ProductPage() {
  const router = useRouter();
  const { productId } = router.query;

  return 
Product Details for Product ID: {productId}
;
}

export default ProductPage;

Example 2: Nested Dynamic Routes

// pages/blog/[category]/[postId].js
import { useRouter } from 'next/router';

function BlogPost() {
  const router = useRouter();
  const { category, postId } = router.query;

  return 
Blog Post in {category} with ID: {postId}
;
}

export default BlogPost;

Example 3: Catch-All Routes

// pages/docs/[...slug].js
import { useRouter } from 'next/router';

function Docs() {
  const router = useRouter();
  const { slug } = router.query;

  return 
Documentation for: {slug.join('/')}
;
}

export default Docs;

Common Questions and Answers

1. What is the difference between static and dynamic routing?

   Static routing involves predefined paths, while dynamic routing generates paths based on data or user input.

2. How does Next.js handle dynamic routing under the hood?

   Next.js uses the file system as the main API. Dynamic routes are created using bracket syntax in the pages directory.

3. Can I have multiple dynamic segments in a single route?

   Yes, you can have multiple dynamic segments, like /users/[userId]/posts/[postId].

4. What happens if a dynamic route doesn’t match any data?

   Next.js will render the page, but you can handle this case by checking if the data exists and displaying a 404 or error message.

5. How do I prefetch data for dynamic routes?

   You can use getStaticProps or getServerSideProps to fetch data at build time or request time.

Troubleshooting Common Issues

• 404 Error on Dynamic Route

  Ensure the file name matches the dynamic segment and the URL is correct.

• Query Parameters Not Available

  Check if the useRouter hook is correctly imported and used.

• Data Fetching Issues

  Verify your data fetching logic and ensure the API or data source is accessible.

Practice Exercises

1. Create a dynamic route for a user settings page with the URL structure /settings/[section].
2. Implement a nested dynamic route for a project management app with the URL /projects/[projectId]/tasks/[taskId].
3. Experiment with catch-all routes by creating a documentation site with URLs like /docs/[...slug].

Remember, practice makes perfect! 💪 Keep experimenting with dynamic routes, and soon you’ll be a pro at creating flexible, dynamic web applications with Next.js.

For more information, check out the Next.js documentation on dynamic routing.