Simplifying Data Fetching with Redux Toolkit's RTK Query
Tags: react, redux, webperf, webdev
Published: 2024-03-12 20:14:31

## Introduction

Redux Toolkit (RTK) has become a popular choice for managing application state in React projects. But managing data fetching logic within Redux often involves writing boilerplate code. Enter RTK Query: an optional add-on for RTK that simplifies data fetching and caching.

**What is RTK Query?**

RTK Query is a powerful tool designed to streamline data fetching and caching in your React applications. It leverages the core functionalities of RTK, like `createSlice` and `createAsyncThunk`, to automate common data fetching tasks. This eliminates the need for manual code related to:

* Making API requests
* Handling response parsing
* Caching data
* Managing loading states

**Benefits of Using RTK Query**

* **Reduced Boilerplate:** RTK Query automates much of the data fetching logic, freeing you to focus on component logic and UI.
* **Built-in Caching:** Data is automatically cached, improving performance by reusing previously fetched data.
* **Automatic Request Deduplication:** RTK Query ensures only one request is made for the same data, even if multiple components request it simultaneously.
* **React Hooks:** RTK Query generates React hooks that encapsulate data fetching and provide convenient access to data and loading states within your components.
* **TypeScript Support:** RTK Query is fully written in TypeScript, offering excellent type safety and developer experience.

**Getting Started with RTK Query: A Code Example**

Here's a basic example demonstrating how to use RTK Query to fetch a list of posts:

```javascript
import { createSlice, configureStore } from '@reduxjs/toolkit';
import { fetchBaseQuery } from '@reduxjs/toolkit/query/react';

const initialState = { posts: [], loading: false };

const postsSlice = createSlice({
  name: 'posts',
  initialState,
  reducers: {},
  extraReducers: (builder) => {
    builder
      .addQuery('fetchPosts', async () => {
        // Simulate API call
        return await new Promise((resolve) => setTimeout(() => resolve([{ id: 1, title: 'Post 1' }], 1000)));
      })
  },
});

export const store = configureStore({
  reducer: {
    posts: postsSlice.reducer,
  },
  middleware: (getDefaultMiddleware) =>
    getDefaultMiddleware().concat(fetchBaseQuery()),
});

// Accessing data and loading state in your component
import { useGetPostsQuery } from './postsSlice';

function PostsList() {
  const { data, isLoading } = useGetPostsQuery();

  return (
    <div>
      {isLoading ? (
        <p>Loading posts...</p>
      ) : (
        <ul>
          {data.map((post) => (
            <li key={post.id}>{post.title}</li>
          ))}
        </ul>
      )}
    </div>
  );
}
```

In this example, the `fetchPosts` query is defined within the `postsSlice` using `builder.addQuery`. RTK Query automatically generates a `useGetPostsQuery` hook that can be used in your components to access the fetched data and loading state.

**Comparison with Tanstack React-Query**

Both RTK Query and Tanstack React-Query are popular solutions for data fetching in React applications. Here's a brief comparison:

| Feature                 | RTK Query                                 | Tanstack React-Query              |
|-------------------------|---------------------------------------------|-----------------------------------|
| Integration              | Integrates seamlessly with Redux Toolkit     | Standalone library                 |
| Caching                  | Built-in caching with customizable options  | Built-in caching with customizable options  |
| Mutation Handling        | Requires separate mutation definitions      | Built-in mutation handling         |
| TypeScript Support      | Fully written in TypeScript                | Fully written in TypeScript        |
| Documentation & Community | Extensive documentation and active community | Extensive documentation and active community |

**Choosing Between RTK Query and React-Query**

The choice between these libraries depends on your project setup and preferences. Here are some factors to consider:

* **Redux Usage:** If you're already using Redux Toolkit, RTK Query offers a tightly integrated solution with minimal additional setup.
* **Mutation Handling:** If your application requires frequent mutations, React-Query might be a better choice due to its built-in mutation handling.
* **Standalone Library Preference:** If you prefer a standalone library for data fetching, React-Query is a strong option.

**Conclusion**

RTK Query is a powerful addition to the Redux Toolkit ecosystem, simplifying data fetching and caching for React applications. It offers a streamlined approach with built-in data caching and other advanced features.

**Resources**
- Redux [RTK Query](https://redux-toolkit.js.org/rtk-query/overview)
- react-query aka [Tanstack Query](https://tanstack.com/query/latest/docs/framework/react/overview)