Скачать или смотреть Resolving the React State Not Updating Issue Due to Cleanup in Custom Hooks

Discover how to tackle the frustrating problem of React state not updating because of cleanup in your custom hooks. Learn effective techniques to ensure your components update as intended.
---
This video is based on the question https://stackoverflow.com/q/67646626/ asked by the user 'Lygis' ( https://stackoverflow.com/u/14304819/ ) and on the answer https://stackoverflow.com/a/67646883/ provided by the user 'ale917k' ( https://stackoverflow.com/u/11895568/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: react/ state not being updated because of cleanup

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding State Update Issues in React

In the world of React development, encountering state not updating correctly can be a common, yet frustrating issue. Specifically, you might have come across situations where your state appears to be stubborn, only refreshing upon a full component reload. This typically happens when your component’s setup isn’t properly managing the lifecycle of its hooks.

The Problem: State Not Updating with Cleanup

Let’s illustrate this problem with a common scenario: you're building a custom hook that retrieves user information for posts being created. You design your component in such a way that it announces when it's mounted or unmounted, relying on a mounted reference. However, when your cleanup logic is in place, you notice that your state appears to have been frozen, updating only after a browser refresh.

Here’s a snippet from a typical implementation:

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

The main issue arises from how mounted is being handled.

The Solution: Properly Managing Component State

Step 1: Modify the Mounted Check

Instead of using a reference that persists across renders, redefine your mounted variable directly within your useEffect. This approach ensures that you're getting the correct value of mounted when the effect runs.

Here’s how you can rewrite the useEffect:

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

Step 2: Why This Works

Lifecycle Handling: By resetting mounted inside useEffect, you allow React to manage the lifecycle of your component more effectively. This means you can capture whether or not the component is still "active" when your state updates are called.

Avoiding Stale Data: Using mounted.current could lead to referencing outdated data. By utilizing a local variable, you ensure that you're always checking the most current state of your component.

Conclusion

In conclusion, managing component state in React surely comes with its challenges, but being mindful of how you implement cleanup logic can save you from a lot of headache. By redefining your mounted check directly within the useEffect, you can ensure that your state updates occur seamlessly and as expected.

Key Takeaways:

Localize mounted within the effect to ensure it reflects the current state.

Always test your hooks to confirm state updates without needing a manual refresh.

Implement these changes, and you'll find that your React components behave more predictably and as intended.

Happy coding!