Deep Instruction · Phases 21–25
Forms + TanStack Query — Professional Frontend Data Flow
Build reliable forms, cache server state, handle mutations, and reason about optimistic concurrency.
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React Hook Form + Zod Contract
Keep field mechanics separate from validation semantics.
Mapping Server Validation Errors Back to Forms
Treat server failures as structured form feedback where appropriate.
Query Keys as Cache Identity
Design keys that encode every input affecting server data.
Freshness, staleTime, and Refetching
Make cache freshness a UX/business choice.
Mutations and Invalidation
After server writes, decide which cached views became uncertain.
Optimistic Update with Snapshot and Rollback
Make the UI fast without pretending the server cannot reject writes.
Choose URL, Local, Form, or Server State
Put each value where its lifecycle naturally belongs.
Capstone: Production Task Editor
Combine query, form, mutation, errors, optimistic behavior, and cache repair.