How to use Incremental Static Regeneration (ISR) in Next.js to update blog posts periodically after their initial publication.

Question

You are developing a blog using Next.js with the Page Router technology and wish to leverage Incremental Static Regeneration (ISR) for your blog posts. Each article is statically generated at the time of the build, but you want them to update periodically after their initial publication to ensure fast loading speeds and fresh data. Here is a code snippet from the article page :

```
// pages/posts/[postId].js
export async function getStaticProps({ params }) {
  const postData = await getPostData(params.postId);
  return {
    props: {
      postData,
    },
    revalidate: 10 // time in seconds
  };
}

export async function getStaticPaths() {
  const paths = getAllPostIds();
  return {
    paths,
    fallback: 'blocking'
  };
}

// ...
```

Accepted Answer

`revalidate: 10` in `getStaticProps` regenerates the page every 10 seconds, but only if a request is made after this interval has expired.

Answer

Incremental Static Regeneration (ISR) is not supported by Next.js and requires a custom caching solution.

Answer

ISR cannot be used with `fallback: 'blocking'` in getStaticPaths; it requires fallback: true.

Answer

`revalidate: 10` means that the page will be regenerated in the background every 10 seconds, regardless of user requests.

Question from the Next.js test

How to use Incremental Static Regeneration (ISR) in Next.js to update blog posts periodically after their initial publication.