Request waterfalls
React chapter 101 · Web Perf · ch.10 / Advanced React ch.14 · source: Nadia Makarevich, Advanced React ch.14 and Web Performance Fundamentals ch.10
The problem
useEffect fetches the user, then another effect fetches posts(user.id). The second request cannot start until the first paint-and-effect. Network idle time stacks. RSC/loaders (33, 55) exist because this pattern is slow.
The pattern that fixes it
Start independent requests together (Promise.all / render-as-you-fetch). If B needs A’s id, have the server join them, or fetch a precomputed envelope. Do not hide waterfalls behind sequential await in a single effect either.
Keep learning
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