Next.js automatically determines that a page is static (can be prerendered) if it has no blocking data requirements. This determination is made by the absence of getServerSideProps
and getInitialProps
in the page.
This feature allows Next.js to emit hybrid applications that contain both server-rendered and statically generated pages.
Statically generated pages are still reactive: Next.js will hydrate your application client-side to give it full interactivity.
One of the main benefits of this feature is that optimized pages require no server-side computation, and can be instantly streamed to the end-user from multiple CDN locations. The result is an ultra fast loading experience for your users.
If getServerSideProps
or getInitialProps
is present in a page, Next.js will switch to render the page on-demand, per-request (meaning Server-Side Rendering).
If the above is not the case, Next.js will statically optimize your page automatically by prerendering the page to static HTML.
During prerendering, the router's query
object will be empty since we do not have query
information to provide during this phase. After hydration, Next.js will trigger an update to your application to provide the route parameters in the query
object.
Note: Parameters added with dynamic routes to a page that's using
getStaticProps
will always be available inside thequery
object.
next build
will emit .html
files for statically optimized pages. For example, the result for the page pages/about.js
would be:
.next/server/pages/about.html
And if you add getServerSideProps
to the page, it will then be JavaScript, like so:
.next/server/pages/about.js
App
with getInitialProps
then this optimization will be turned off in pages without Static Generation.Document
with getInitialProps
be sure you check if ctx.req
is defined before assuming the page is server-side rendered. ctx.req
will be undefined
for pages that are prerendered.