Ryan tells Sam about some experiments he’s been running using Server Components in Vercel’s new edge runtime. He talks about how components that suspend in the node runtime cause the static build of your Next.js app to wait until they unsuspend, while components that suspend in the edge runtime stream back fallback responses as data is being fetched. Ryan also tells Sam about a blocking JS trick he learned to alter the initial render of your clientside app based on client-specific data, like whether their theme preference is dark or light mode.

Topics include:

• 0:00 - Intro
• 1:00 - Running synchronous JS before React’s initial render of build-time generated HTML
• 17:03 - Using getServerSideProps on the edge in Next.js for run-time generated HTML
• 32:15 - Behavior of Server Components that suspend in edge runtime vs. node runtime

Links:

• Josh Comeau’s post on dark mode
• Next.js discussion on switchable runtime