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React Query Method

🔍 Introduction to React Query​

React Query is a powerful data-fetching and state management library designed for React applications. It simplifies data fetching by providing automatic caching, background updates, and smart refetching, eliminating the need for manual state management.

Unlike traditional useEffect and useState approaches, React Query reduces boilerplate code, enhances performance, and improves the developer experience. It efficiently handles complex data-fetching logic, making it a preferred choice for modern React applications.

🌟 Why Use React Query?​

While using useEffect with fetch() or custom hooks works, they have limitations, such as:

❌ No built-in caching (data refetches every time the component mounts).
❌ No automatic background updates.
❌ Manual state management for loading and errors.
❌ No automatic retries or stale data handling.

✅ React Query addresses these issues by providing:

✔️ Caching – Prevents unnecessary API calls by storing responses.
✔️ Automatic Refetching – Keeps data up to date without extra effort.
✔️ Error Handling & Retries – Handles network failures automatically.
✔️ Parallel & Dependent Queries – Fetch multiple or sequential queries efficiently.
✔️ Background Updates – Refreshes stale data without UI blocking.
✔️ Simplified State Management – Eliminates the need for useState and useEffect.

⚙️ Setting Up React Query​

📦 Installation​

First, install React Query and its DevTools:

npm install @tanstack/react-query

For debugging and better visibility into queries, install the React Query DevTools:

npm install @tanstack/react-query-devtools

🏗 Setting Up QueryClientProvider​

Before using React Query, wrap your application with QueryClientProvider in index.js or _app.js (for Next.js):

import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
import { ReactQueryDevtools } from '@tanstack/react-query-devtools';

const queryClient = new QueryClient();

function MyApp({ Component, pageProps }) {
  return (
    <QueryClientProvider client={queryClient}>
      <Component {...pageProps} />
      <ReactQueryDevtools initialIsOpen={false} />
    </QueryClientProvider>
  );
}

export default MyApp;

🚀 Fetching Data with useQuery​

React Query’s useQuery hook simplifies data fetching:

import { useQuery } from "@tanstack/react-query";

const fetchData = async () => {
  const response = await fetch("https://api.example.com/data");
  if (!response.ok) throw new Error("Network response was not ok");
  return response.json();
};

export default function DataComponent() {
  const { data, error, isLoading } = useQuery({ queryKey: ["data"], queryFn: fetchData });

  if (isLoading) return <p>Loading...</p>;
  if (error) return <p>Error: {error.message}</p>;

  return <pre>{JSON.stringify(data, null, 2)}</pre>;
}

🧐 How It Works​

  1. Define a Fetch Function – Fetches data from an API.
  2. Use useQuery Hook:
    • queryKey: Unique identifier for caching (e.g., ["data"]).
    • queryFn: Function responsible for fetching data.
  3. Automatic State Management:
    • isLoading: Tracks loading state.
    • error: Captures API errors.
    • data: Stores the fetched data.
  4. Render UI Dynamically: Displays loading, error, or data states.

🔄 Automatic Refetching & Caching​

React Query automatically refetches data based on various triggers:

useQuery({
  queryKey: ["data"],
  queryFn: fetchData,
  refetchInterval: 5000, // Auto-refetch every 5 seconds
  staleTime: 10000, // Data remains fresh for 10 seconds
});

✨ Advanced Features​

  • Refetch on Window Focus: Automatically refetches data when the user switches back to the tab.
  • Polling: Fetch data at regular intervals.
  • Cache Time: Determines how long data remains in cache before being garbage collected.

🏎 Fetching with Dynamic Parameters​

Pass query parameters dynamically using queryKey:

const { data } = useQuery({
  queryKey: ["user", userId], // Triggers refetch when userId changes
  queryFn: () => fetchUser(userId),
});

Pros of React Query​

Advantages​

✔️ Automatic State Management – Reduces the need for useState and useEffect.
✔️ Built-in Caching – Minimizes redundant API calls.
✔️ Optimized Performance – Fetches data efficiently in the background.
✔️ Retries & Error Handling – Provides robust network request handling.
✔️ Improved User Experience – Keeps UI responsive with seamless updates.

⚠️ When to Avoid React Query?​

🚫 If your app doesn’t make frequent API calls, using useEffect might be sufficient.
🚫 If you need global state management, React Query is not a replacement for Redux or Zustand.
🚫 If API responses rarely change, static site generation (SSG) might be a better choice.

🎯 Conclusion​

React Query is an essential tool for efficient, scalable, and maintainable data fetching in React applications. It eliminates boilerplate code, improves performance, and simplifies state management.

For modern applications that rely on API interactions, React Query is a game-changer!