Understanding the getStaticPaths + getStaticProps vs. useRouter in Next.js

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The Problem

Imagine you have a simple book-listing site where users can view details about various books. The URL for a book page might look something like this: localhost:3000/books/book1. You have two different methods to fetch the book data based on the book ID from the URL:

Using getStaticPaths and getStaticProps

Using useRouter().query

While both methods are functional, they operate differently, leading to different results in terms of performance and data management.

Solution Breakdown: getStaticPaths + getStaticProps

How It Works

Compile Time Execution: The primary distinction is that getStaticPaths and getStaticProps function during compile time. This means that when you run the build command (next build), these functions will generate the HTML for your pages once. As a result, they deliver a consistent HTML output for every user who visits that specific page.

Code Example:

[[See Video to Reveal this Text or Code Snippet]]

Advantages:

Fast loading times since the HTML is pre-built.

Great for content that doesn't change frequently.

Disadvantages:

Requires a rebuild each time there's an update to the book data.

Solution Breakdown: useRouter

How It Works

Run Time Execution: On the other hand, using useRouter fetches data on page load, which means when a user visits the page, their browser will send a request to get the book data. This happens after your components are rendered, hence it incorporates JavaScript after the initial page load.

Code Example:

[[See Video to Reveal this Text or Code Snippet]]

Advantages:

Always shows the latest data since it fetches on every visit.

Useful for dynamic content that changes frequently.

Disadvantages:

Slower initial page load as data is fetched during the rendering process.

Increased requests to your server.

Choosing the Best Approach: When to Use Which Method

Considerations

Content Stability: If your book data rarely changes, getStaticPaths and getStaticProps are preferable for faster loading and pre-rendered pages.

Dynamic Content Updates: If your book list changes often or you need to reflect real-time updates, consider using the useRouter() method.

Combination of Both: In certain cases, a hybrid approach can be useful. For example, you might load the main book data using getStaticProps but fetch the latest reviews with useRouter(), ensuring optimal performance with up-to-date content.

Conclusion

Final Thoughts