What is the main difference between React Query and Redux?

React Query and Redux are two libraries for managing state in React applications, but they have distinct focuses and use cases.

1. Design Purpose:

   • React Query is specifically designed for handling asynchronous data (server state), such as fetching data from APIs, caching results, and data synchronization.
   • Redux is a more general-purpose state management library that provides a predictable state container for JavaScript applications, primarily used for managing client-side state (UI state).

2. Data Caching and Invalidations:

   • React Query includes built-in mechanisms for data caching and automatic invalidation. It automatically re-fetches data in the background and marks it as stale when data becomes outdated.
   • Redux itself does not provide these features directly. Implementing data caching and invalidation in Redux typically requires additional middleware or manual logic.

3. Data Synchronization and Updates:

   • React Query provides built-in tools for handling data queries, mutations, updates, and synchronization, reducing boilerplate code.
   • Redux requires manual management of data synchronization and updates, often involving writing actions, reducers, and using middleware for asynchronous logic, which can increase boilerplate.

4. Configuration and Boilerplate:

   • React Query is typically more concise to use, with hooks like useQuery and useMutation enabling direct data requests within components.
   • Redux configuration is relatively complex, especially during initial setup, requiring definitions of actions, reducers, and store creation, though Redux Toolkit reduces some boilerplate.

5. Development Philosophy:

   • React Query aims to simplify server state handling by encouraging direct data loading from components without global state overhead.
   • Redux follows Functional Programming principles, using pure reducers and immutable data to manage state, facilitating easier state change tracking and time-travel debugging.

6. Community and Ecosystem:

   • React Query is popular for asynchronous data management but has a smaller ecosystem focused on data fetching and caching.
   • Redux boasts a large community and ecosystem with numerous middleware and libraries, such as redux-thunk, redux-saga, reselect, and redux-form.

Example:

Suppose your application needs to fetch a user list from a REST API and display the latest data. Using React Query, you can do this:

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

function UsersComponent() {
  const { data, error, isLoading } = useQuery('users', fetchUsers);

  // Render your UI based on the data, error, and loading state...
}

In this example, fetchUsers is an asynchronous function that requests data from the API. useQuery automatically handles data loading, caching, re-fetching, and updates.

In Redux, you might need to create actions and reducers to handle asynchronous requests and use middleware like redux-thunk:

jsx
import { useDispatch, useSelector } from 'react-redux';

function UsersComponent() {
  const dispatch = useDispatch();
  const { users, error, isLoading } = useSelector(state => state.users);

  useEffect(() => {
    dispatch(fetchUsers());
  }, [dispatch]);

  // Render your UI based on the users, error, and loading state...
}

React Query and Redux are two distinct libraries serving different roles in React applications.

React Query is a library for data fetching, caching, synchronization, and updates. It focuses on asynchronous data operations, such as API data retrieval, caching results, and automatic re-fetching. Key features include:

• Automatic Caching and Invalidations: React Query automatically caches request results and provides mechanisms to re-fetch data when changes occur.
• Background Synchronization: Supports automatic updates in the background during data changes or user interactions.
• Query State: Provides rich state information (e.g., loading, error, data states) for UI display.
• Minimal Global State Management: Aims to manage server state with minimal configuration.

Redux is a library providing a predictable state container for JavaScript applications, particularly suited for React. It manages global application state through actions and reducers. Key features include:

• Global State Management: Uses a single state tree with changes managed via dispatched actions and reducers.
• Predictability: Ensures consistent behavior through a clear state change process.
• Middleware: Supports extensions like redux-thunk for asynchronous handling and logging.
• Development Tools: Includes tools like Redux DevTools for tracking state changes and action dispatches.

Key Differences:

1. Purpose: React Query is primarily for data synchronization, while Redux is for global state management.
2. Data Management: React Query includes built-in caching mechanisms, whereas Redux requires manual handling of data requests and responses.
3. State Synchronization: React Query provides automatic synchronization, while Redux needs additional libraries (e.g., redux-thunk) for asynchronous logic.
4. Configuration: React Query reduces boilerplate, while Redux requires more setup steps.
5. Development Experience: React Query's API aligns with React hooks, while Redux demands adherence to specific patterns and best practices.

For example, fetching a user list with React Query:

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

function Users() {
  const { isLoading, error, data } = useQuery('fetchUsers', fetchUsersApi);

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

  return (
    <ul>
      {data.map(user => (
        <li key={user.id}>{user.name}</li>
      ))}
    </ul>
  );
}

async function fetchUsersApi() {
  const response = await fetch('/api/users');
  if (!response.ok) {
    throw new Error('Network response was not ok');
  }
  return response.json();
}

Using Redux for the same task:

javascript
import { createStore, applyMiddleware } from 'redux';
import thunk from 'redux-thunk';
import { Provider, useDispatch, useSelector } from 'react-redux';

// Action types
const FETCH_USERS_REQUEST = 'FETCH_USERS_REQUEST';
const FETCH_USERS_SUCCESS = 'FETCH_USERS_SUCCESS';
const FETCH_USERS_FAILURE = 'FETCH_USERS_FAILURE';

// Action creators
const fetchUsersRequest = () => ({ type: FETCH_USERS_REQUEST });
const fetchUsersSuccess = users => ({ type: FETCH_USERS_SUCCESS, payload:

React Query and Redux are two distinct libraries that serve different roles in React applications.

React Query is a library designed for data fetching, caching, synchronization, and updates. It specializes in handling asynchronous data operations, such as retrieving data from APIs, caching results, and automatically refetching data. Here are some key features of React Query:

• Automatic caching and invalidation: React Query automatically caches the results of each request and provides a mechanism for refetching data when changes occur.
• Background synchronization: Supports automatic data updates in the background during data changes or user interactions.
• Query state: React Query provides comprehensive state information, including loading, error, and data states, facilitating easy UI integration.
• Minimal global state management: React Query aims to manage server state with minimal configuration.

Redux is a library that provides a predictable state container for JavaScript applications, particularly suited for use with React. It is primarily used for managing and maintaining the global state of an application, and provides a pattern for updating and accessing this state. Here are some key features of Redux:

• Global state management: Redux provides a single global state tree, where all state changes are managed through dispatched actions and reducers.
• Predictability: Since all state changes follow a defined process, application behavior is highly predictable.
• Middleware: Redux supports using middleware to extend functionality, such as handling asynchronous calls and logging.
• Development tools: Redux offers powerful tools like Redux DevTools, which help developers track state changes and action dispatches.

Key differences:

1. Purpose: React Query is primarily used for data synchronization, while Redux is used for global state management.
2. Data management: React Query includes built-in mechanisms for data fetching and caching, whereas Redux requires developers to manually manage data requests and response results.
3. State synchronization: React Query provides automatic data synchronization mechanisms, while Redux requires additional libraries (such as redux-thunk or redux-saga) to handle asynchronous logic.
4. Configuration: React Query reduces the need for configuration and boilerplate code, while Redux requires more boilerplate code and configuration steps.
5. Development experience: React Query's API design aligns closely with React's hooks pattern, while Redux typically requires adherence to specific design patterns and best practices.

For example, if we have a user list and want to fetch these users using React Query, we might do the following:

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

function Users() {
  const { isLoading, error, data } = useQuery('fetchUsers', fetchUsersApi);

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

  return (
    <ul>
      {data.map(user => (
        <li key={user.id}>{user.name}</li>
      ))}
    </ul>
  );
}

async function fetchUsersApi() {
  const response = await fetch('/api/users');
  if (!response.ok) {
    throw new Error('Network response was not ok');
  }
  return response.json();
}

Using Redux to handle the same data fetching requires writing action creators, reducers, and corresponding async action handlers:

javascript
import { createStore, applyMiddleware } from 'redux';
import thunk from 'redux-thunk';
import { Provider, useDispatch, useSelector } from 'react-redux';

// Action types
const FETCH_USERS_REQUEST = 'FETCH_USERS_REQUEST';
const FETCH_USERS_SUCCESS = 'FETCH_USERS_SUCCESS';
const FETCH_USERS_FAILURE = 'FETCH_USERS_FAILURE';

// Action creators
const fetchUsersRequest = () => ({ type: FETCH_USERS_REQUEST });
const fetchUsersSuccess = users => ({ type: FETCH_USERS_SUCCESS, payload:

React Query and Redux are two libraries for managing state in React applications, but they have notable differences in their focus areas and use cases.

1. Design Purpose:

   • React Query is specifically designed for handling asynchronous data (server state), such as fetching data from APIs, caching data, and synchronizing data.
   • Redux is a more general-purpose state management library that provides a predictable state container for JavaScript applications, used for managing client-side state (UI state).

2. Data Caching and Expiration:

   • React Query includes built-in mechanisms for data caching and automatic expiration. It can automatically refetch data in the background and mark data as stale when it becomes outdated.
   • Redux itself does not directly provide these features. To implement data caching and expiration in Redux, additional middleware or manual implementation of the relevant logic is typically required.

3. Data Synchronization and Updates:

   • React Query provides built-in tools for handling data queries, mutations, updates, and synchronization, minimizing boilerplate code when used.
   • Redux requires manual management of data synchronization and updates, often involving the creation of actions, reducers, and the use of middleware to handle asynchronous logic, which can lead to more boilerplate code.

4. Configuration and Boilerplate Code:

   • React Query is typically more concise to use, providing hooks such as useQuery and useMutation that allow you to directly initiate data requests within components.
   • Redux configuration and usage are relatively complex, especially during initial project setup. You need to define actions, reducers, and create a store, although Redux Toolkit can help reduce some boilerplate code.

5. Development Philosophy:

   • React Query tends to provide a simplified approach for handling server state, encouraging you to load data directly from within components without needing to store all data in a global state management system.
   • Redux follows the principles of Functional Programming, managing and updating state using pure functions (reducers) and immutable data, which makes it easier to track state changes and perform time-travel debugging.

6. Community and Ecosystem:

   • React Query is popular for asynchronous data management, but its ecosystem is smaller compared to Redux, as it focuses more on data fetching and caching.
   • Redux has a large community and ecosystem, including many middleware and additional libraries such as redux-thunk, redux-saga, reselect, and redux-form.

Example:

Suppose your application needs to fetch a list of users from a REST API and you want to display the latest data. With React Query, you can do this:

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

function UsersComponent() {
  const { data, error, isLoading } = useQuery('users', fetchUsers);

  // Render your UI based on the data, error, and loading state...
}

In this example, fetchUsers is an asynchronous function that requests data from the API. useQuery automatically handles data loading, caching, refetching, and updates.

In Redux, you might need to create actions and reducers to handle asynchronous requests and use middleware such as redux-thunk to handle asynchronous logic:

jsx
import { useDispatch, useSelector } from 'react-redux';

function UsersComponent() {
  const dispatch = useDispatch();
  const { users, error, isLoading } = useSelector(state => state.users);

  useEffect(() => {
    dispatch(fetchUsers());
  }, [dispatch]);

  // Render your UI based on the users, error, and loading state...

Note: The code block is incomplete in the original, but it is preserved as provided for accuracy.

React Query is a specialized library designed specifically for API caching. It handles API caching exclusively—nothing else. Because it's purpose-built for this task, it excels with minimal code.

On the other hand, Redux provides flexible tools that can store almost any data—but you must implement the logic yourself. Therefore, you can achieve more with Redux, though you may need to write code that a dedicated library like React Query doesn't require.

You can use them in parallel: API caching in React Query, and the rest of your global state in Redux.

Specifically, the official Redux Toolkit includes an API caching abstraction called RTK Query (starting from version 1.6), which offers a similar feature set to React Query but differs in overall design—you might want to explore it.