React/Next.js Standards

React 19 Best Practices

• Use Suspense, the use hook, and promises as props
• Prefer use, useTransition, and startTransition over useEffect
• You probably shouldn't use useEffect

Component Design

• Keep components pure: don't declare constants or functions inside components
• Use React Query for client-side async data fetching
• Don't fetch data in useEffect

Loading & Error States

• Prefer <Suspense> and useSuspenseQuery over React Query's isLoading
• Use errorBoundary with retry button

Cache Management

• Don't use magic strings for cache tags; use an enum/factory
• Use enum for React Query cache strings

Avoid

• Magic numbers/strings
• Data fetching in useEffect
• Constants inside component bodies
• isLoading patterns when Suspense works