React Query
Tags: react, javascript, typescript, webdev
Published: 2023-01-06 09:47:35


## What is react-query / tanstack query ?

React Query, now known as the Tan Stack Query, is a powerful tool for managing and fetching data in your React application. It was designed to be lightweight and easy to use, making it a popular choice for developers looking to streamline their data management processes.

One of the main benefits of React Query is its ability to handle data fetching and caching automatically. When you make a request for data, React Query will first check to see if the data is already stored in its cache. If it is, the cached data will be returned immediately, resulting in a much faster response time for the user. If the data is not in the cache, React Query will make a request to the server to fetch the data and then store it in the cache for future use.

Another key feature of React Query is its ability to handle real-time updates to data. When a request is made to update data on the server, React Query will automatically refetch the data and update the cache, ensuring that your application always has the most up-to-date information. This is especially useful for applications that rely on real-time data, such as social media feeds or messaging apps.

One of the more advanced features of React Query is its support for pagination and infinite scrolling. This allows you to load large datasets in smaller chunks, making it easier to manage and reducing the load on your server. It also provides a better user experience, as the user can scroll through data indefinitely without having to manually click through pages.

React Query also makes it easy to handle errors and retries. If a request fails, React Query will automatically retry the request a set number of times before giving up. It will also handle error display for you, making it easy to let the user know if something has gone wrong.

Overall, React Query is a powerful tool for managing and fetching data in your React application. Its automatic caching, real-time updates, pagination support, and error handling make it a great choice for developers looking to streamline their data management processes.

## What problems does react-query solve?

React Query is a tool for managing and fetching data in a React application. It was designed to solve several common problems that developers often encounter when working with data in a React app, such as:

- **Managing data fetching**: Fetching data from an API or other external source can be a complex and error-prone process. React Query makes it easy to fetch and cache data, automatically retrying failed requests and handling error display for you.

- **Real-time data updates**: In many applications, data is constantly changing on the server and it is important to keep the client up to date with the latest information. React Query makes it easy to fetch and update data in real-time, ensuring that your application always has the most up-to-date information.

- **Pagination and infinite scrolling**: When working with large datasets, it is often necessary to split the data up into smaller chunks to make it more manageable. React Query provides support for pagination and infinite scrolling, allowing you to load data in smaller chunks and providing a better user experience.

- **Caching and performance**: Caching data can significantly improve the performance of your application, particularly for data that does not change frequently. React Query automatically caches data and can be configured to cache data for a specific period of time, ensuring that your application is fast and responsive.

Overall, React Query helps developers solve a variety of data management challenges in their React applications, making it easier to build powerful and efficient apps.

## Practical examples of react-query

Here are a few examples of how you might use React Query in your application:

**Infinite scrolling**:

```jsx
import { useQuery } from "react-query";

function App() {
  const { status, data, error, isFetching } = useQuery(
    ["posts", { page: 1 }],
    () => fetch(`https://my-api.com/posts?page=1`).then((res) => res.json())
  );

  const handleScroll = () => {
    if (
      window.innerHeight + document.documentElement.scrollTop !==
      document.documentElement.offsetHeight
    )
      return;

    setPage((prevPage) => prevPage + 1);
  };

  useEffect(() => {
    window.addEventListener("scroll", handleScroll);
    return () => window.removeEventListener("scroll", handleScroll);
  }, []);

  if (isFetching) return "Loading...";
  if (error) return "An error occurred";

  return (
    <div>
      {data.posts.map((post) => (
        <div key={post.id}>{post.title}</div>
      ))}
    </div>
  );
}
```

In this example, we are using the useQuery hook to fetch a page of posts from an API endpoint. The handleScroll function is used to detect when the user has scrolled to the bottom of the page, and when this occurs, the page number is incremented and a new query is triggered to fetch the next page of data. This allows the user to scroll through an infinite number of pages of data.

**Fetching data**:

```jsx
import { useQuery } from "react-query";

function App() {
  const { status, data, error, isFetching } = useQuery("user", () =>
    fetch(`https://my-api.com/user`).then((res) => res.json())
  );

  if (isFetching) return "Loading...";
  if (error) return "An error occurred";

  return (
    <div>
      <h1>{data.user.name}</h1>
      <p>{data.user.email}</p>
    </div>
  );
}
```

In this example, we are using the useQuery hook to fetch a single user from an API endpoint. The hook handles all of the caching and error handling for us, making it easy to display the data to the user.

I hope these examples give you a good idea of how you can use React Query in your own application. There are many more features and capabilities available, so be sure to check out the documentation for more information.

## Conclusion

In conclusion, React Query is a powerful tool for managing and fetching data in a React application. It simplifies common data management tasks such as fetching, caching, and real-time updates, making it a great choice for developers looking to streamline their data management processes. Its support for pagination and infinite scrolling, as well as error handling and retries, make it a comprehensive solution for data management in React. If you are looking to improve the way you manage data in your React app, React Query is definitely worth considering.