Resolving useEffect Multiple Re-renders in React: Managing Async API Calls

Описание: Discover how to effectively handle multiple re-renders with `useEffect` in React when making asynchronous API calls in your Quiz app. Learn the right way to implement the abort controller for smoother data fetching.
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This video is based on the question https://stackoverflow.com/q/73190866/ asked by the user 'Sharanjeet Singh' ( https://stackoverflow.com/u/19172195/ ) and on the answer https://stackoverflow.com/a/73191750/ provided by the user 'Martin PELCAT' ( https://stackoverflow.com/u/14614728/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving useEffect Multiple Re-renders in React: Managing Async API Calls

Creating a dynamic React application can sometimes lead to unexpected challenges, especially when dealing with asynchronous tasks like API calls. One common issue developers encounter is multiple re-renders, which can significantly affect application performance and user experience.

In this guide, we'll dive into a specific scenario faced while building a quiz app using the Trivia API, where a single API call leads to multiple state updates and UI changes, resulting in a less-than-optimal user experience. Let’s decode this problem and explore a straightforward solution.

The Problem

The author of a quiz app using the Trivia API observed that upon making an API call, the application state changed three times and the UI updated twice within just one second. The code utilized useEffect with an empty dependency array, which ideally should mean that the effect runs only once on component mount. However, the behavior indicated otherwise.

Here is a brief recap of the existing API call structure:

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

Understanding the Cause

In React 18, the behavior of useEffect can be affected by the development mode lifecycle. This can sometimes cause re-renders due to the way React handles state updates and effects. When an asynchronous call is made, if the component is re-mounted or if there is an outstanding update, multiple renders may occur.

The Solution: Implementing AbortController

To tackle this issue, we can utilize the AbortController. This tool allows you to cancel ongoing fetch requests whenever a component unmounts or before making another API call, thereby ensuring that only one successful API call happens. Here's how to implement it:

Step-by-Step Implementation

Create an instance of AbortController: This will allow us to manage our fetch request.

Pass the signal to the fetch request, enabling it to listen for abort signals.

Handle the abort in the catch block, preventing errors if a request was cancelled.

Here's how the updated useEffect will look:

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

Breakdown of the Code Changes

Abort Controller Initialization: const abortController = new AbortController(); creates a new AbortController instance.

Fetch Request: The fetch call includes signal: abortController.signal to manage its lifespan.

Catch block: The catch checks if the error is due to the request being aborted, ensuring we don't log any irrelevant errors.

Cleanup Function: The return function in useEffect calls abortController.abort(), cancelling any ongoing requests when the component unmounts or the effect re-runs.

Conclusion

By implementing the AbortController, we can effectively manage API calls in React applications involving asynchronous operations. This not only reduces unnecessary re-renders but also enhances the overall responsiveness of the user interface.

Remember, managing your API requests isn’t just about fetching data; it’s also about ensuring a smooth experience for users. Next time you face issues with multiple re-renders in your applications, consider this method as part of your toolkit.

Happy coding with React!