RTK Query in React Apps: What You Need to Know

Brief Overview of RTK Query

Welcome, fellow developers! Today, we will dive into the world of RTK Query, a powerful tool that's part of the Redux Toolkit package. RTK Query simplifies data fetching and caching in your Redux applications, making it a must-have in your front-end development toolkit.

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Purpose of the Blog Post

This blog post aims to provide a comprehensive guide to RTK Query, from its basic concepts to its advanced features. Whether you're just starting out with RTK Query or looking to deepen your understanding, this post is for you. We'll also explore how you can leverage WiseGPT, a generative AI for React developers, to enhance your RTK Query experience. So, let's get started!

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Understanding

Definition

RTK Query is a library part of the Redux Toolkit, specifically designed to simplify data fetching, caching, and state updates in your Redux applications. It provides developers with utilities to efficiently manage remote data fetching and caching in a Redux store.

This means you can fetch, cache, and sync server state in your applications without writing any additional code.

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RTK Query vs React Query: The Differences

While RTK Query and React Query are powerful tools for data fetching and synchronization in React, they have some key differences. React Query is a standalone library that isn't tied to Redux and focuses solely on fetching, caching, and updating data.

On the other hand, RTK Query is part of the Redux Toolkit and integrates seamlessly with other Redux features.

RTK Query's functionality extends beyond just data fetching and caching. It also generates Redux action creators and reducers for you, which can be a significant time-saver. Additionally, RTK Query's API slices automatically handle the transformation of API responses into the normalized state, which can be a complex task to handle manually.

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Should You Use Redux Toolkit Query or React Query?

The choice between RTK Query and React Query largely depends on your specific needs and the complexity of your project. If you're already using Redux in your project and want a solution that integrates well with your existing Redux code, RTK Query is a great choice.

It's also a good option if you want to minimize the amount of boilerplate code you have to write.

On the other hand, if you're not using Redux, or if you're working on a project where data fetching and caching are the primary concerns, React Query might be a better fit. It's also worth noting that React Query has a larger community and more resources available, which can be beneficial if you run into any issues.

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Diving Deeper into React RTK Query

Core Features

RTK Query comes packed with a host of features that make data fetching and caching a breeze. Here are some of the key features:

1. Automatic Caching: It automatically caches data from your API calls, saving you the trouble of manually managing a cache. It also invalidates the cache, ensuring your app always has the most up-to-date data.
2. Automatic Refetching: It can automatically refetch data when certain conditions are met, such as when the app re-focuses or network re-connectivity.
3. Automatic State Updates: With it, you don't need to write extra reducers or actions for managing your API state. It automatically generates these for you.
4. Optimistic Updates and Undo: It supports optimistic updates, which means it can update the UI instantly upon changes and then sync with the server in the background. RTK Query can automatically revert the UI to its previous state if the server update fails.
5. Polling: It supports polling at regular intervals, which is useful for keeping data up-to-date in real-time applications.

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How it Works?

At the heart of RTK Query is the createApi function. This function lets you define an API slice, which includes the base URL for your API, endpoints for fetching data, and optional configurations for things like caching and polling.

Each endpoint you define with createApi generates a set of Redux actions and a reducer for managing the state of that endpoint. This includes activities for initiating a fetch, receiving the response, or handling any errors.

When you call one of these generated actions in your component, RTK Query automatically handles sending the API request, caching the response data, and updating the Redux state.

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RTK Query with React Native: Is it Possible?

Yes, you can use RTK Query with React Native! It is platform-agnostic and works with any Redux setup, including React Native projects. This means you can leverage the same powerful data fetching and caching capabilities in your mobile apps as in your web apps.

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Practical Application

Setting up a New React Project

Before using RTK Query, let's set up a new React project. You can do this by running the following command in your terminal:

1     npx create-react-app rtk-query-demo
2     

This will create a new React project named rtk-query-demo. Once the project is set up, navigate into the project directory:

1     cd rtk-query-demo
2     

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Adding Redux Toolkit to Your React App

Next, let's add the Redux Toolkit to our React app. You can do this by running the following command:

npm install @reduxjs/toolkit react-redux

This will install the Redux Toolkit and the React-Redux library, allowing us to connect our Redux store to our React components.

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Creating Your First Query

Now that our project is set up, let's create our first RTK Query. We'll start by defining an API slice using the createApi function from RTK Query.

1     import { createApi, fetchBaseQuery } from '@reduxjs/toolkit/query/react'
2    
3    export const api = createApi({
4      reducerPath: 'api',
5      baseQuery: fetchBaseQuery({ baseUrl: '/api' }),
6      endpoints: (builder) => ({
7        getPosts: builder.query({
8          query: () => 'posts',
9        }),
10      }),
11    })
12    
13    export const { useGetPostsQuery } = api
14     

In this code, we're defining an API slice with a single endpoint for fetching posts. The createApi function generates a custom hook for this endpoint, which we can use in our components to fetch data.

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Fetching Data

Now that we have our API slice and custom hook, we can use them in our components to fetch data. Here's an example of how you might do this in a component:

1     import React from 'react'
2    import { useGetPostsQuery } from './api'
3    
4    function Posts() {
5      const { data: posts, isLoading } = useGetPostsQuery()
6    
7      if (isLoading) return 'Loading...'
8    
9      return (
10        <div>
11          {posts.map((post) => (
12            <h2 key={post.id}>{post.title}</h2>
13          ))}
14        </div>
15      )
16    }
17    
18    export default Posts
19     

In this component, we're using the useGetPostsQuery hook to fetch data. This hook returns an object with several properties, including data and isLoading, which we can use to display our posts or a loading message.

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Caching Data

One of the great things about RTK Query is that it automatically caches data from your API calls. If you call the same API endpoint multiple times, RTK Query will return the cached data instead of making a new API request. This can significantly improve your app's performance and reduce the load on your server.

You can control the caching behaviour of RTK Query by configuring the cacheTime and staleTime options in your API slice.

The cacheTime option controls how long data is kept in the cache after it's no longer being used, while the staleTime option controls how long data is considered fresh and doesn't need to be refetched.

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Advanced Techniques

Using RTK Query for CRUD Operations

RTK Query isn't just for fetching data - you can also use it for creating, updating, and deleting data. Each of these operations corresponds to a different type of RTK Query endpoint: query endpoints for fetching data, and mutation endpoints for creating, updating, or deleting data.

Here's an example of how you might define a mutation endpoint for creating a new post:

1     import { createApi, fetchBaseQuery } from '@reduxjs/toolkit/query/react'
2    
3    export const api = createApi({
4      reducerPath: 'api',
5      baseQuery: fetchBaseQuery({ baseUrl: '/api' }),
6      endpoints: (builder) => ({
7        getPosts: builder.query({
8          query: () => 'posts',
9        }),
10        createPost: builder.mutation({
11          query: (newPost) => ({
12            url: 'posts',
13            method: 'POST',
14            body: newPost,
15          }),
16        }),
17      }),
18    })
19    
20    export const { useGetPostsQuery, useCreatePostMutation } = api
21     

This code defines a createPost mutation endpoint that makes a POST request to the 'posts' URL. The createPost endpoint takes a newPost object as a parameter, which it includes in the request's body.

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Optimistic Updates

Optimistic updates are a technique where you update the UI as if a certain action has already completed, without waiting for the server response. This can make your app feel faster and more responsive to the user.

RTK Query supports optimistic updates out of the box. You can enable optimistic updates for a mutation endpoint by providing an onQueryStarted function in the endpoint definition. This function should update the cache with the expected result of the mutation.

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Custom Middleware

RTK Query is built on top of Redux Toolkit's createAsyncThunk and createSlice functions, which means you can use it with custom middleware just like any other Redux action.

For example, you might add a custom middleware that logs all API requests and responses. You can do this by defining a middleware function and adding it to your Redux store:

1     import { configureStore } from '@reduxjs/toolkit'
2    import { api } from './api'
3    
4    const loggerMiddleware = (storeAPI) => (next) => (action) => {
5      if (api.endpoints.getPosts.match(action)) {
6        console.log('Fetching posts:', action)
7      } else if (api.endpoints.createPost.match(action)) {
8        console.log('Creating post:', action)
9      }
10    
11      return next(action)
12    }
13    
14    export const store = configureStore({
15      reducer: {
16        [api.reducerPath]: api.reducer,
17      },
18      middleware: (getDefaultMiddleware) =>
19        getDefaultMiddleware().concat(loggerMiddleware),
20    })
21     

In this code, we're defining a loggerMiddleware function that logs any actions related to the getPosts and createPost endpoints. We then add this middleware to our Redux store using the configureStore function.

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