React Query Best Practices for Performance Optimization

React Query has revolutionized how we handle server state management in React applications. When implemented correctly, it can significantly boost your app’s performance and user experience. Let’s dive into some battle-tested best practices that will help you optimize your React Query implementation.

Understanding Query Keys

The foundation of efficient React Query usage lies in proper query key management. Think of query keys as your data’s unique identifier - similar to how you’d organize files in a filing cabinet.

// ❌ Don't: Use overly simple keys
useQuery(['users'])

// ✅ Do: Use specific, structured keys
useQuery(['users', { status: 'active', role: 'admin' }])

Mastering Cache Management

One of React Query’s superpowers is its sophisticated caching system. However, with great power comes great responsibility. Let’s explore how to make the most of it.

Stale Time vs. Cache Time

Think of staleTime as your data’s freshness timer and cacheTime as its expiration date. Setting these correctly can dramatically improve your application’s performance:

const { data } = useQuery(['products'], fetchProducts, {
  staleTime: 5 * 60 * 1000, // 5 minutes
  cacheTime: 30 * 60 * 1000 // 30 minutes
})

Implementing Intelligent Prefetching

Prefetching is like preparing tomorrow’s breakfast tonight - it’s all about anticipating needs before they arise.

// Prefetch on hover
const prefetchTodoOnHover = async (todoId) => {
  await queryClient.prefetchQuery(
    ['todo', todoId],
    () => fetchTodoById(todoId)
  )
}

Optimizing Network Requests

Implementing Parallel Queries

When you need multiple pieces of data simultaneously, parallel queries can be your best friend:

function Dashboard() {
  const userQuery = useQuery(['user'], fetchUser)
  const projectsQuery = useQuery(['projects'], fetchProjects)
  const notificationsQuery = useQuery(['notifications'], fetchNotifications)
}

Leveraging Background Updates

Keep your UI responsive while updating data in the background:

const { data, refetch } = useQuery('todos', fetchTodos, {
  refetchOnWindowFocus: true,
  refetchOnReconnect: true
})

Error Handling and Retry Logic

Implement robust error handling to ensure your application gracefully handles failures:

useQuery(['data'], fetchData, {
  retry: 3,
  retryDelay: attemptIndex => Math.min(1000 * 2 ** attemptIndex, 30000)
})

Conclusion

Remember, performance optimization is not a one-time task but an ongoing process. Regularly monitor your application’s performance and adjust these strategies based on your specific use cases and requirements.