Book Image

State Management with React Query

By : Daniel Afonso
Book Image

State Management with React Query

By: Daniel Afonso

Overview of this book

State management, a crucial aspect of the React ecosystem, has gained significant attention in recent times. While React offers various libraries and tools to handle state, each with different approaches and perspectives, one thing is clear: state management solutions for handling client state are not optimized for dealing with server state. React Query was created to address this issue of managing your server state, and this guide will equip you with the knowledge and skills needed to effectively use React Query for state management. Starting with a brief history of state management in the React ecosystem, you’ll find out what prompted the split from a global state to client and server state and thus understand the need for React Query. As you progress through the chapters, you'll see how React Query enables you to perform server state tasks such as fetching, caching, updating, and synchronizing your data with the server. But that’s not all; once you’ve mastered React Query, you’ll be able to apply this knowledge to handle server state with server-side rendering frameworks as well. You’ll also work with patterns to test your code by leveraging the testing library and Mock Service Worker. By the end of this book, you'll have gained a new perspective of state and be able to leverage React Query to overcome the obstacles associated with server state.
Table of Contents (14 chapters)
Part 1: Understanding State and Getting to Know React Query
Part 2: Managing Server State with React Query

Using only the object format

In v4 of React Query, most custom hooks and functions were overloaded to support previous patterns. This means that in your code, both of the useQuery hooks in the following snippet would be the same thing:

const { data } = useQuery({
    queryKey: ["api"]
    queryFn: fetchData,
const { data } = useQuery(["api"], fetchData);

As you can see from the preceding snippet, we create a query with queryKey ["api"] and queryFn fetchData twice. This is because the second and first examples are just instances of the same hook that has been overloaded.

With the introduction of v5, the second example shown in the preceding snippet is no longer supported; therefore, you can only use your hooks by passing them a single object with the needed options. Here is the syntax that you need to follow from now on:

useQuery({ queryKey, queryFn, ...options })
useMutation({ mutationFn, ...options...