sim-hooks.mdc

---
description: Custom hook patterns and best practices
globs: ["apps/sim/**/use-*.ts", "apps/sim/**/hooks/**/*.ts"]
---

# Hook Patterns

## Structure

```typescript
interface UseFeatureProps {
  id: string
  onSuccess?: (result: Result) => void
}

export function useFeature({ id, onSuccess }: UseFeatureProps) {
  // 1. Refs for stable dependencies
  const idRef = useRef(id)
  const onSuccessRef = useRef(onSuccess)

  // 2. State
  const [data, setData] = useState<Data | null>(null)
  const [isLoading, setIsLoading] = useState(false)

  // 3. Sync refs
  useEffect(() => {
    idRef.current = id
    onSuccessRef.current = onSuccess
  }, [id, onSuccess])

  // 4. Operations (useCallback with empty deps when using refs)
  const fetchData = useCallback(async () => {
    setIsLoading(true)
    try {
      const result = await fetch(`/api/${idRef.current}`).then(r => r.json())
      setData(result)
      onSuccessRef.current?.(result)
    } finally {
      setIsLoading(false)
    }
  }, [])

  return { data, isLoading, fetchData }
}
```

## Rules

1. Single responsibility per hook
2. Props interface required
3. Refs for stable callback dependencies
4. Wrap returned functions in useCallback
5. Always try/catch async operations
6. Track loading/error states