Скачать или смотреть Update Mouse Position with useState in React

Learn how to effectively track and store mouse positions in React using `useState`. This guide explains the solution to continuously capture and update mouse coordinates in an array as you move the mouse.
---
This video is based on the question https://stackoverflow.com/q/68707261/ asked by the user 'young' ( https://stackoverflow.com/u/16004249/ ) and on the answer https://stackoverflow.com/a/68707342/ provided by the user 'young' ( https://stackoverflow.com/u/16004249/ ) 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: How to update mouse position with useState

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.
---
Update Mouse Position with useState in React: A Step-by-Step Guide

Tracking the mouse position can be a vital feature in many web applications. However, ensuring that these positions are continuously updated and stored effectively can pose a challenge. If you’ve faced issues where your mouse position values reset after stopping the mouse movement, this post will guide you through a solution using React's useState and useEffect hooks.

The Problem

While working with mouse events in React, one might encounter the need to capture the mouse's coordinates as it moves. The initial attempt often looks like this: create an event listener that pushes the current mouse position into an array. However, a common pitfall is that the array resets every time you stop moving the mouse.

Here’s a simplified version of the code that illustrates the issue:

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

In this code snippet, the array positionArray keeps getting reset upon stopping the mouse movement, which is not desirable for tracking the mouse's history accurately.

The Solution

The solution to this problem is quite simple. Instead of using a standalone positionArray, we can leverage the power of setRoute to dynamically update the previous state without losing the values when the mouse stops moving. Here’s how to do it step-by-step:

Step 1: Use setRoute Correctly

The key lies in the way setRoute is called. Instead of pushing the new position into a separate array, we'll use the updater function provided by setRoute. This way, we ensure that we constantly have access to the most up-to-date state.

Updated Code

Here’s how the final implementation should look:

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

Explanation of the Changes

Using setRoute(prevRoute => [...prevRoute, position]):

This allows each new mouse position to append to the existing state.

The arrow function provides access to the previous state, and by spreading prevRoute, the new position is added to the array without losing previous entries.

useEffect Dependencies:

Notice how useEffect has an empty dependency array []. This ensures that the event listener is only set once when the component mounts and cleaned up properly when it unmounts.

Conclusion

By following the steps outlined in this guide, you can effectively capture, store, and update mouse positions continuously while overcoming common pitfalls that result in data loss. Harnessing useState in conjunction with event listeners can create responsive and engaging user experiences in your React applications. Happy coding!