fix: preprocessor options for the default preprocessor

[itsyoboieltr]

Types of changes

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• typo fix
• docs change
• breaking change

Motivation / Use-Case

When using HtmlBundlerPlugin with only preprocessorOptions and relying on the default preprocessor, the options were silently ignored.

Example:

new HtmlBundlerPlugin({
  // no explicit `preprocessor` set, rely on default
  preprocessorOptions: { useWith: false },
  // ...
});

In this case, preprocessorOptions never reached the loader or the preprocessor.

Breaking Changes

None.

The behavior only changes for configurations where preprocessorOptions were previously ignored when using the default preprocessor. In those cases, the options now correctly take effect as originally intended.

Additional Info

Root cause:

In PluginService.init, preprocessorOptions were only copied into loaderOptions inside the conditional that checks for an explicitly defined preprocessor. When preprocessor is not set (default preprocessor), this condition is false, and preprocessorOptions are never forwarded.

Fix:
Keep the preprocessor assignment guarded as before and move the preprocessorOptions assignment out of that guard so it always propagates when defined, even for the default preprocessor.

This aligns behavior with user expectations and the documented configuration pattern: preprocessorOptions should work whether or not preprocessor is explicitly set.

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have updated the CHANGELOG.md.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Appreciation for the useful project

• Do not forget to give a star ⭐

[webdiscus]

@itsyoboieltr

The use of preprocessor options was intentionally applyed only when the preprocessor itself is explicitly specified.
But your improvement might also make sense.
Thank you!

[webdiscus]

@itsyoboieltr , the new v4.22.0 is released. Thank you.