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Oct 13, 2025 by magicalceylontours.com 16 views

HMR Not Updating Style from an Imported Source: A Critical Issue in Astro 5.4.2

Hot Module Replacement (HMR) is a powerful feature in web development that allows developers to update and reload specific modules without requiring a full page reload. However, in Astro 5.4.2, a critical issue has been identified where HMR fails to update styles from imported sources. This article delves into the problem, its implications, and potential solutions.

To better understand the issue, let's take a look at the Astro environment:

Astro Info

Astro                    v5.4.2
Node                     v20.16.0
System                   macOS (arm64)
Package Manager          npm
Output                   static
Adapter                  none
Integrations             @astrojs/react

As we can see, the issue is occurring in Astro 5.4.2, with Node.js 20.16.0 and macOS (arm64) as the system environment.

The issue is not limited to a specific browser, but rather affects both Chrome and Firefox.

Describe the Bug

During development, when updating a CSS property that resides in an imported file, the HMR never updates the page. Therefore, the new value never gets applied.

To make matters worse, the CSS file is imported within Astro's frontmatter. This means that the issue is not related to the way the CSS file is imported, but rather to the way HMR handles styles from imported sources.

Interestingly, the issue was not present in Astro 4.16. This suggests that the problem was introduced in a later version of Astro, likely due to changes in the way HMR handles styles.

A similar issue has been reported on the Astro GitHub page (https://github.com/withastro/astro/issues/12275). However, this issue is not the same as the one described here.

A minimal reproducible example of the issue can be found at https://codesandbox.io/p/devbox/nervous-voice-3ry3l8.

The expected result is that the page should update when the CSS has changed from any imported file.

If you are willing to submit a pull request for this issue, please indicate your willingness to do so.

While the exact cause of the issue is still unknown, there are a few potential solutions that can be explored:

Update Astro to the latest version: It's possible that the issue has been fixed in a later version of Astro.
Use a different CSS import method: Instead of importing the CSS file within Astro's frontmatter, try importing it using a different method, such as using a CSS module or a CSS-in-JS solution.
Disable HMR for CSS files: If the issue is specific to CSS files, try disabling HMR for these files and see if the issue persists.

In conclusion, the issue of HMR not updating styles from imported sources in Astro 5.4.2 is a critical problem that affects both Chrome and Firefox. While the exact cause of the issue is still unknown, there are potential solutions that can be explored. If you are willing to submit a pull request for this issue, please indicate your willingness to do so.

If you are experiencing this issue, we recommend trying the following:

Update Astro to the latest version: This may resolve the issue.
Use a different CSS import method: This may resolve the issue.
Disable HMR for CSS files: This may resolve the issue.

In the future, we plan to investigate the issue further and provide a more detailed explanation of the cause and potential solutions.

We would like to thank the Astro community for their contributions to this issue.

Astro GitHub page: https://github.com/withastro/astro/issues/12275
Minimal reproducible example: https://codesandbox.io/p/devbox/nervous-voice-3ry3l8

For further information, please refer to the Astro documentation: https://astro.build/docs/.
HMR Not Updating Style from an Imported Source: A Q&A Article

In our previous article, we discussed the critical issue of HMR not updating styles from imported sources in Astro 5.4.2. In this article, we will provide a Q&A section to address some of the most frequently asked questions related to this issue.

A: Hot Module Replacement (HMR) is a feature in web development that allows developers to update and reload specific modules without requiring a full page reload. This is particularly useful during development, as it enables developers to see the changes they make in real-time without having to reload the entire page.

A: If HMR is not updating styles from imported sources, it can lead to a range of issues, including:

Inconsistent styling: The styles from the imported source may not be updated, leading to inconsistent styling across the application.
Broken layout: The layout of the application may break if the styles from the imported source are not updated.
Difficulty in debugging: It can be challenging to debug issues related to styling if HMR is not updating styles from imported sources.

A: The issue is specific to Astro 5.4.2 because it is a regression from the previous version of Astro. This means that the issue was not present in earlier versions of Astro, but was introduced in Astro 5.4.2.

A: You can reproduce the issue by following these steps:

Create a new Astro project using Astro 5.4.2.
Import a CSS file within Astro's frontmatter.
Update the CSS property in the imported file.
Observe that the HMR does not update the page.

A: Some potential solutions to this issue include:

Update Astro to the latest version: It's possible that the issue has been fixed in a later version of Astro.
Use a different CSS import method: Instead of importing the CSS file within Astro's frontmatter, try importing it using a different method, such as using a CSS module or a CSS-in-JS solution.
Disable HMR for CSS files: If the issue is specific to CSS files, try disabling HMR for these files and see if the issue persists.

A: Yes, if you are willing to submit a pull request for this issue, please indicate your willingness to do so.

A: You can find more information about this issue on the Astro GitHub page (https://github.com/withastro/astro/issues/12275) and in the minimal reproducible example (https://codesandbox.io/p/devbox/nervous-voice-3ry3l8).

In conclusion, the issue of HMR not updating styles from imported sources in Astro 5.4.2 is a critical problem that affects both Chrome and Firefox. We hope that this Q&A article has provided some useful information and insights into this issue. If you have any further questions or concerns, please don't hesitate to reach out.

If you are experiencing this issue, we recommend trying the following:

Update Astro to the latest version: This may resolve the issue.
Use a different CSS import method: This may resolve the issue.
Disable HMR for CSS files: This may resolve the issue.

In the future, we plan to investigate the issue further and provide a more detailed explanation of the cause and potential solutions.

We would like to thank the Astro community for their contributions to this issue.

Astro GitHub page: https://github.com/withastro/astro/issues/12275
Minimal reproducible example: https://codesandbox.io/p/devbox/nervous-voice-3ry3l8

For further information, please refer to the Astro documentation: https://astro.build/docs/.