How do I validate data update using react- query

What is React Query and its primary use cases?

React Query is a robust data synchronization library designed for managing server state in React applications, including loading, caching, synchronizing, and updating data from REST or GraphQL APIs. It is particularly well-suited for scenarios requiring frequent data retrieval from the server and maintaining up-to-date data.

Fundamental Concepts of Data Validation in React Query

In React Query, 'data validation' typically refers to ensuring cached data remains current. This can be achieved through several approaches:

1. Background Updates: React Query implements this via periodic polling of backend data or automatic refetching upon window focus restoration.
2. Invalidation After Mutations: After executing operations that modify server data (mutations), related queries can be invalidated, prompting a refetch on subsequent queries.

Practical Example of Data Validation with React Query

Suppose we have a simple application where users can view and edit articles. We can leverage React Query to fetch the article list and validate data after users complete edits.

Step 1: Setting Up React Query

First, configure the React Query client and provider.

jsx
import { QueryClient, QueryClientProvider } from 'react-query';

const queryClient = new QueryClient();
const App = () => (
  <QueryClientProvider client={queryClient}>
    <MyComponent />
  </QueryClientProvider>
);

Step 2: Using useQuery to Fetch Articles

jsx
import { useQuery } from 'react-query';

function FetchArticles() {
  const { data, error, isLoading } = useQuery('articles', fetchArticles);

  if (isLoading) return 'Loading...';
  if (error) return 'An error occurred: ' + error.message;

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

Here, fetchArticles is a function that calls the API and returns article data.

Step 3: Using useMutation and invalidateQueries for Data Validation

When users update an article, use the useMutation hook to update data and invalidate the article list query upon success to trigger fetching the latest data.

jsx
import { useMutation, useQueryClient } from 'react-query';

function UpdateArticle() {
  const queryClient = useQueryClient();

  const { mutate } = useMutation(updateArticleApi, {
    onSuccess: () => {
      // Invalidate the 'articles' query to ensure data freshness
      queryClient.invalidateQueries('articles');
    },
  });

  const handleSubmit = (article) => {
    mutate(article);
  };

  return <form onSubmit={handleSubmit}>...</form>;
}

Summary

By utilizing React Query's useMutation and invalidateQueries, we ensure related data is validated and updated after user modifications. This approach minimizes unnecessary data fetches while guaranteeing the user interface always displays the latest data—critical for complex data interactions and state synchronization.