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Discover why using `VueUse.useMouse()` without reactive bindings results in static mouse coordinates. Learn how to fix this common issue with clear, organized steps.
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Understanding VueUse.useMouse(): Why Is Your Mouse Position Always 0?

If you've been experimenting with Vue.js and the VueUse library, you may have encountered a puzzling issue: using VueUse.useMouse() results in your mouse position always being 0. This can be incredibly frustrating, especially when you're trying to track mouse movements in real-time. In this guide, we'll explore why this happens and how to effectively resolve the issue.

The Problem

When using the useMouse function from the VueUse library, many developers log the mouse's x and y coordinates within a setInterval function. Interestingly, these coordinates appear to update in the console, but they remain 0 when displayed in the HTML element (for example, within a <span> tag).

Example Code

Here's a snippet of code that illustrates the problem:

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

When this is run, the console shows the mouse movements, but the span will always display 0 | 0. So, what’s going wrong here?

Understanding VueUse and Reactivity

The key to solving this problem lies in understanding Vue.js reactivity. The mouse coordinates returned by VueUse.useMouse() are reactive properties. To properly use these reactive properties and reflect updates in your component, they need to be correctly integrated within the Vue application's reactive system.

Why the Coordinates Remain Static

When you do not declare the reactive properties (like x and y) correctly, Vue will not be able to react to their changes in the component's template. Additionally, using certain module types combined with incorrect imports can lead to issues where the reactive properties are not tracked correctly by Vue's reactivity system.

The Solution

The original issue can be resolved by ensuring that the correct Vue and VueUse modules are imported and used properly. Below is a step-by-step guide to fixing the issue:

Update Your Imports:
Make sure to import both vue and vueuse/core correctly. Use the recommended import paths for the library versions you are using. Here’s the correct way to set up your imports:

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

Modify Your Component Setup:
Use the returned values from useMouse() directly in the component without additional processing that could obstruct reactivity:

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

Expected Outcome

With these updates, you should see that the mouse coordinates now reflect accurately in both the console and the displayed HTML when you move your mouse around. The span element will no longer show 0 | 0, and will instead display the current mouse position dynamically.

Conclusion

Tracking mouse movements in a Vue.js application using VueUse can be a straightforward process, as long as the reactive properties are correctly set up and imported. By following the provided solution, you’ll be able to seamlessly integrate mouse position tracking into your application. If you encounter other issues, always ensure that your imports and reactive data are being used as intended.

If you found this guide helpful, feel free to share it with others who might be struggling with the same issue!