RSC usage, "use client" directive, and Component Purity.
Next.js (App Router) uses React Server Components (RSC) by default.
useState, useEffect, or Browser APIs (window, localstorage).'use client' at the VERY TOP of the file.onClick), State (useState), Lifecycle effects, Browser APIs.<Button /> in a Client Component.children prop to the Client Component.// ClientWrapper.tsx
'use client';
export default function ClientWrapper({ children }) {
return <div>{children}</div>;
}
// Page.tsx (Server)
<ClientWrapper>
<ServerComponent />
</ClientWrapper>;
server-only package to prevent).