performance-optimizer

Optimize FlatList by providing getItemLayout for fixed-height items, setting maxToRenderPerBatch, windowSize, and initialNumToRender, and enabling removeClippedSubviews on Android. Use stable renderItem and keyExtractor callbacks via useCallback instead of inline functions.

Fix N+1 queries in Prisma by using include to fetch related records in a single query instead of looping over results with separate findMany calls. For GraphQL resolvers, use the DataLoader pattern to batch and group related queries by foreign key.

Use React.memo for expensive components that re-render unnecessarily, useMemo for expensive calculations that should only recompute when dependencies change, and useCallback to keep function references stable for memoized children. Avoid memoizing trivial components where overhead exceeds benefit.

Create composite indexes matching common WHERE and ORDER BY clauses, such as (user_id, created_at DESC) for paginated history queries. Use partial indexes for filtered subsets like active records, and verify usage with pg_stat_user_indexes to drop unused indexes.

Memory leaks commonly come from uncleared setInterval timers and unremoved event listeners in useEffect hooks. Always return a cleanup function from useEffect that clears timers and removes listeners when the component unmounts.

Reduce bundle size by lazy loading heavy screens with React.lazy and Suspense, importing specific functions or subpaths from libraries like lodash instead of the whole package, and removing unused dependencies from package.json.