Part 77: Understanding Dynamic Rendering and Caching in Next.js

[App] Pagination

[App] Pagination

In the world of web development, efficient data handling and rendering strategies are crucial for providing an optimal user experience. One of the features that can significantly affect performance and scalability is pagination. In this post, we’ll explore how pagination is implemented in Next.js and delve into the nuances of dynamic rendering and caching.

Implementing Pagination with PaginationBar

With our PaginationBar component in place, users can seamlessly browse through reviews fetched from a Content Management System (CMS). The navigation is intuitive, with the next link disabled on the last page, preventing users from navigating beyond available content.

Dynamic Rendering with searchParams

In our ReviewsPage, we employ searchParams to manage pagination. Next.js documentation notes that searchParams is a dynamic API, meaning the page will be dynamically rendered at request time. This is because the values passed as query parameters are unpredictable, making static generation at build time impractical.

How Dynamic Rendering Works

When you perform a production build and start the server, you’ll notice that routes using searchParams are marked as dynamic, indicated by a special symbol. This tells us that Next.js has identified these routes to be rendered at runtime.

Upon reloading the Reviews page, server logs reveal that the page is rendered dynamically. This includes prefetching links to adjacent pages, such as the first and second pages, enhancing user navigation by loading potential next steps in advance.

Static vs. Dynamic Rendering

Although dynamic rendering is convenient, you might wonder if static rendering is possible for paginated routes. It can be achieved by using path parameters instead of query strings. For example, URLs could be structured as /reviews/page/1, /reviews/page/2, etc. This allows for predefining page numbers and generating static pages using a generateStaticParams function.

However, the decision between using path parameters and searchParams depends on the nature of the parameters. If they represent a finite set of options, static rendering makes sense. Conversely, if parameters create unique, user-specific pages, dynamic rendering is more appropriate.

Caching in Dynamic Rendering

Dynamic rendering doesn’t necessarily mean data is refetched on every request. In our setup, Next.js uses the fetch cache by default. This means that once data is fetched, it is cached and reused for subsequent requests, unless invalidated by changes in the CMS.

For instance, after visiting the first few pages, Next.js caches the data. Reloading these pages doesn’t trigger additional CMS requests, as the data is already available locally. However, visiting a new page will make a request to fetch and cache new data.

The Impact of Caching

Caching plays a crucial role in optimizing performance. Although dynamic rendering is inherently slower than serving static files, caching reduces the need for repeated data fetching, thus speeding up page rendering. This balance between dynamic content and efficient data retrieval is key to maintaining a responsive user experience.

Conclusion

By understanding the interplay between dynamic rendering and caching in Next.js, we can build applications that efficiently handle pagination and data fetching. While dynamic routes offer flexibility, caching ensures that performance remains robust. As you design your Next.js applications, consider these strategies to optimize both user experience and server load.