Solving State Management Challenges with useQuery and useState in React Native

Discover how to effectively manage state in React Native by leveraging `useQuery` and `useEffect`, avoiding common pitfalls for seamless data handling.
---

Visit these links for original content and any more details, such as alternate solutions, comments, revision history etc. For example, the original title of the Question was: React Query useQuery() and useState()

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Managing State Fetching in React Native: useQuery and useState

In modern React Native development, especially when using libraries like React Query, achieving efficient data fetching and state management can become a challenge. Developers often find themselves struggling to synchronize data fetched from APIs with local component state. This is particularly evident when trying to update component state based on asynchronous queries. Here, we will explore how to use useQuery from React Query effectively, alongside useState and useEffect, to avoid common pitfalls.

The Problem: Initialization of State with Fetched Data

You may find yourself in a situation where you fetch data using useQuery, manage that data using useState, and then aim to update the state inside child components. The challenge often arises during the initialization of the state once the data is fetched. Attempting to handle this directly in useQuery can throw errors like "data is undefined" or lead to infinite re-renders.

Common Issues Encountered

Direct State Updates in select: Attempting to set state inside the select function can lead to complications and unexpected behaviors because select is not designed for side effects.

Misconfigured useEffect Hooks: Using useEffect incorrectly, either before or after the call to useQuery, can create unforeseen issues, such as attempting to read properties of undefined data or rendering the hooks incorrectly.

Excessive Renders: Calling state updates directly in the rendering lifecycle can lead to an overwhelming number of re-renders, eventually hitting the "too many re-renders" error.

The Solution: Structure Your Code for Success

The recommended approach is to separate your concerns: fetching data, monitoring changes, and updating state with a clear workflow. Below is an effective implementation.

Step 1: Set Up the Component

Start by defining your initial state and necessary hooks:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Use useQuery to Fetch Data

Make your data fetching call using useQuery, but don’t try to set the state here:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Update State with useEffect

Utilize useEffect to monitor changes in the data returned from useQuery, which will allow your component to react only when new data arrives:

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Handle Loading and Error States

Make sure to handle loading states and potential errors gracefully to improve the user experience. Here is an example check:

[[See Video to Reveal this Text or Code Snippet]]

Step 5: Render the Component UI

Now you can render your component UI utilizing the leadPreferences data:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By separating the data fetching logic from state management and effectively using useEffect, you can streamline your component logic and avoid the common pitfalls associated with asynchronous data handling in React Native. This structure not only keeps your code organized but also enhances the maintainability of your application.

In summary, when navigating the complexities of useQuery and useState, remember:

Avoid side effects inside select.

Use useEffect to react to state changes from queries.

Always handle loading and errors for better UX.

This ensures a smoother development process, allowing you to create more responsive and efficient applications.