Optimizing Performance and Refetching with React Query

Introduction:

Performance optimization is crucial for creating fast and responsive web applications. In this blog post, we'll explore how to optimize performance and efficiently refetch data using React Query.

We'll cover practical use cases, including query result caching, the stale-while-revalidate pattern, manual data refetching withqueryClient.refetchQueries, and automatic data refetching with query invalidation.

By the end, you'll have a solid understanding of these concepts and be able to optimize performance while ensuring data freshness in your React applications.

Query Result Caching and Stale-While-Revalidate:

Example 1: Query Result Caching

import { useQuery } from 'react-query';

const fetchUserData = async (userId) => {
  // Fetch user data based on the provided user ID
};

const UserProfile = ({ userId }) => {
  const { data } = useQuery(['userData', userId], () => fetchUserData(userId));

  // Render the user profile data
};

In this example, we fetch user data using the useQuery hook. React Query automatically caches the query result based on the query key, which includes the userId. Subsequent requests for the same user data will be served from the cache, improving performance by avoiding unnecessary network requests.

Example 2: Stale-While-Revalidate Pattern

import { useQuery } from 'react-query';

const fetchLatestNews = async () => {
  // Fetch the latest news data
};

const NewsFeed = () => {
  const { data } = useQuery('latestNews', fetchLatestNews, { staleTime: 60000 });

  // Render the news feed with the option for stale data while revalidating in the background
};

In this example, we fetch the latest news data using the useQuery hook. By setting the staleTime option to 60000 (1 minute), React Query allows using stale data while initiating a background revalidation. This pattern improves perceived performance by showing the latest available data to the user immediately and fetching fresh data in the background.

Manual and Automatic Data Refetching:

Example 3: Manual Data Refetching

import { useQuery, useQueryClient } from 'react-query';

const fetchUserData = async (userId) => {
  // Fetch user data based on the provided user ID
};

const UserProfile = ({ userId }) => {
  const queryClient = useQueryClient();
  const { data } = useQuery(['userData', userId], () => fetchUserData(userId));

  const handleRefresh = () => {
    queryClient.refetchQueries('userData');
  };

  // Render the user profile data and implement a manual data refetching mechanism
};

In this example, we fetch user data and display it in the user profile component. By using the queryClient.refetchQueries method, we can manually trigger a data refetch for the 'userData' query key. This enables users to explicitly refresh the data, ensuring they always have the most up-to-date information.

Example 4: Automatic Data Refetching with Query Invalidation

import { useQuery } from 'react-query';

const fetchNewNotifications = async () => {
  // Fetch new notifications data
};

const Notifications = () => {
  const { data } = useQuery('notifications', fetchNewNotifications, { refetchInterval: 30000 });

  // Render the notifications and utilize the automatic data refetching with query invalidation
};

In this example, we fetch new notifications using the useQuery hook. By setting the refetchInterval option to 30000 (

30 seconds), React Query automatically refetches the notifications data every 30 seconds, ensuring users see the latest notifications without manual intervention.

Summary:

• Query result caching and the stale-while-revalidate pattern optimize performance by serving data from the cache and initiating background revalidation.

• Manual data refetching with queryClient.refetchQueries allows users to explicitly refresh the data.

• Automatic data refetching with query invalidation, using options like staleTime and refetchInterval, ensures data freshness without user intervention.

• These concepts empower developers to balance performance and data freshness, enhancing the user experience in React applications.

By applying these optimization techniques, you can create highly performant React applications with up-to-date data. Experiment with these examples, explore React Query's documentation for further customization, and unlock the full potential of performance optimization and data refetching in your projects. Happy coding!