Handling Hydration Errors in React Query

Demonstrate error handling during the hydration process in a React Query application. Show how to catch and handle errors when dehydrating and rehydrating state, ensuring the application remains robust and user-friendly.
import { QueryClient, QueryClientProvider, Hydrate } from 'react-query';
import { useState } from 'react';

function MyApp({ Component, pageProps }) {
  const [queryClient] = useState(() => new QueryClient());

  return (
    <QueryClientProvider client={queryClient}>
      <Hydrate state={pageProps.dehydratedState}>
        <Component {...pageProps} />
This piece initializes React Query with a QueryClient and wraps the app component inside QueryClientProvider and Hydrate components, allowing for dehydrated state to be rehydrated.
import { useQuery, useQueryClient } from 'react-query';

function fetchUserData() {
  // Fetch user data from an API

function UserProfile() {
  const queryClient = useQueryClient();
  const { data, error, isLoading } = useQuery('user', fetchUserData, {
    // Handle rehydration error
    onError: (err) => {
      console.error('Failed to rehydrate user query:', err);
      // Attempt to refetch or handle the error appropriately

  if (isLoading) return <div>Loading...</div>;
  if (error) return <div>An error occurred: {error.message}</div>;

  return <div>{}</div>; // Render user data
Uses useQuery to fetch user data and handle errors during rehydration. If an error occurs (e.g., mismatched state), it invalidates the query causing a refetch, ensuring data consistency.