Что сказать
«loading.tsx и error.tsx — file-based Suspense и error boundaries вокруг page segment. Boundary inside layout, around page — page suspends/throws, shell stays visible, content area → skeleton или error. loading.tsx работает через stream: shell + fallback first, real content later. error.tsx must be client component, props error и reset, catches children errors — не sibling layout — частое misunderstanding. Finer control — inline Suspense вокруг slow widgets, fast parts не ждут slow.»
Итог
Loading/error = segment boundaries inside layout; inline Suspense for widget-level streaming.
Next.js · middle · сложность 5