Is Next.js 15 any good? "use cache" API first look

Summary

This video covers the new caching system introduced in Next.js 15, highlighting the challenges of caching in modern web development and how Next.js addresses them. The update simplifies caching, allowing developers to specify whether to cache or revalidate data for individual routes, components, and server actions. Key features include the new Dynamic IO API, use of suspense boundaries, and the ability to cache specific functions, improving performance and flexibility. Despite some complexity in managing caching at multiple levels, Next.js 15 offers powerful tools to optimize data fetching, rendering, and revalidation. The video also touches on React 19 support and future developments.

Takeaways

• 😀 Next.js 15 introduces a new, intuitive caching system that simplifies caching behavior and offers more control to developers.
• 😀 The new Dynamic IO API allows for explicit control over caching, simplifying the process of deciding which data should be cached and which should be revalidated.
• 😀 By default, Next.js caches server components and fetch requests to optimize performance, but developers can now choose to cache or skip caching for specific parts of their application.
• 😀 To make a page dynamic and re-fetch data on each request, developers can wrap the page in a Suspense boundary, which ensures data loads asynchronously without blocking other page content.
• 😀 Next.js 15 introduces the `use cache` directive, enabling caching of individual components or functions, offering fine-grained control over which parts of an app are cached.
• 😀 Caching can be customized with the `cache life` function, allowing developers to set expiration times for cached data, and it supports manual cache invalidation via the `cache tag` function.
• 😀 Developers can now cache individual server actions and functions, improving flexibility when dealing with multiple data sources with different update frequencies.
• 😀 The caching system in Next.js 15 reduces complexity compared to previous versions but may lead to increasingly complex code as more experimental features are integrated.
• 😀 The new caching system helps avoid issues where outdated data is served because the cache wasn't invalidated or refreshed as expected.
• 😀 Next.js 15 also supports React 19 and the new React compiler, which eliminates the need for certain hooks like `useMemo` and `useCallback` to optimize performance.
• 😀 Although Dynamic IO is experimental in Next.js 15, it marks a step forward in improving caching flexibility and developer experience, despite the possibility of introducing codebase complexity.

Q & A

What are the two primary problems often mentioned in computer science?

The two primary problems mentioned are naming things and caching, along with off-by-one errors.

What major changes were introduced in Next.js 15?

Next.js 15 introduced several new features, such as automatic code migration, a fast turbo pack dev server, a new API for background code execution, and a complete overhaul of caching mechanisms.

How does Next.js handle caching by default?

By default, Next.js caches everything, including server components and any calls to the `fetch` function, to optimize performance by preventing unnecessary re-rendering of the same page.

What is the problem with the default caching behavior in Next.js?

The problem arises when some data needs to be cached while others should be revalidated on each request, leading to complexity in controlling the cache behavior.

What is the new caching API introduced in Next.js 15?

The new caching API is called Dynamic IO, which allows developers to specify exactly which parts of an application should be cached or revalidated, simplifying caching management.

How does the `use cache` directive work in Next.js 15?

The `use cache` directive is used to explicitly cache certain parts of a page or function, allowing more control over how data is cached and revalidated in Next.js 15.

What is the default cache expiration behavior in Next.js 15?

The default cache expiration in Next.js 15 is infinite, with cache revalidation occurring every 15 minutes, which is suitable for content that doesn't change frequently.

Can developers customize the cache expiration in Next.js 15?

Yes, developers can customize the cache expiration using the `cache life` function, or they can invalidate the cache on-demand using the `cache tag` function.

How does the `Suspense` boundary help in dynamic data fetching?

The `Suspense` boundary helps by allowing the page to render immediately while waiting for certain dynamic data (e.g., price) to load in the background, ensuring that the user experience is not blocked.

What is the benefit of using the new caching features in Next.js 15?

The benefit is that it provides developers with more intuitive and flexible caching options, allowing them to cache or revalidate data more easily and reduce the complexity of managing cache in large applications.