Are you familiar with Next.js? What is the difference between SSR, SSG, ISR, and CSR? When would you use each?

Next.js offers several methods for rendering pages:

• SSR (Server-Side Rendering) — the page is generated on the server for each request. Suitable for dynamic content that changes frequently and needs to be up-to-date.

• SSG (Static Site Generation) — pages are generated once during build time and served as static files. Good for content that rarely changes, such as a blog or documentation.

• ISR (Incremental Static Regeneration) — a hybrid of SSG and SSR. Allows updating static pages after deployment with a specified interval (revalidate). Used when you need to serve static content quickly but also want to update it without a full rebuild.

• CSR (Client-Side Rendering) — rendering occurs on the client in the browser using JavaScript. Used for interactive parts of the application where data is loaded dynamically after the page loads.

When to use:

• SSR — for pages with frequently changing data requiring SEO.
• SSG — for static content with infrequent updates.
• ISR — when you want to combine the benefits of SSG and the ability to update data without a full rebuild.
• CSR — for user dashboards where SEO is not critical and interactivity is important.

Example:

// SSR
export async function getServerSideProps() {
  const data = await fetchData();
  return { props: { data } };
}

// SSG
export async function getStaticProps() {
  const data = await fetchData();
  return { props: { data } };
}

// ISR
export async function getStaticProps() {
  const data = await fetchData();
  return { props: { data }, revalidate: 60 };
}