---
description: React 19+ best practices
globs: ["**/*.tsx", "**/*.jsx"]
alwaysApply: true
---

- Function components only. No class components.
- Hooks at the top level. Custom hooks start with `use`.
- Don't store derived state — compute it.
- Don't sync state to state via effects.
- Suspense + `use()` for async data when practical.
- Stable list keys, never the index.