Generating *.meta.js during production build

[Giglium]

This draft PR want to add the feature of the automatic generation of the *.meta.js files. I'm looking for a feedback or a confirmation if this is the appropriate direction.

I'm don't really like the idea to user the replace function to generate the meta filenames, but is the most efficient way that I found since I prefer to avoid to generate twice the metaBlock. Any other ideas ?

In your opinion, we should introduce a flag to enable or disable the generation of these meta files?

Thank you for your feedback!

[Giglium]

Hi @guansss,
Do you had a chance to review this PR?

Thanks for your time!

[guansss]

Hi, sorry for the late response! And thank you for this PR, this is a great feature to have!

I wonder why the meta file goes to chunk.auxiliaryFiles? I haven't used it before so I'm not sure what differences it will make.

Using replace to generate the meta filename is definitely okay since the js output's filename is fixed as *.user.js. But there is a pitfall in .replace("user", "meta"), where something like "user-blocker.user.js" will be converted to "meta-blocker.user.js". It should probably be .replace(/\.user\.js$/, ".meta.js").

Having a flag would be nice. I imagine something like options.meta.file or options.meta.outFile?

[Giglium]

Thanks for the review! Certainly, regex is the most robust way to perform the replace avoiding problems.

For the auxiliaryFiles I have used this guide as a reference: webpack/webpack#11425 (comment)
I understand that we should use them for any file generated during the build that is not a .js or .css. For this reason, I used them.

For the flag, I was thinking something like options.meta.generate with true as the default value. The options.meta.file or options.meta.outFile let me think of having the option to specify the meta filename or output file but I won't provide this possibility...or we should?

In the next few days, I will update the PR with the modifications.

[guansss]

Thanks for the update!

In my opinion, the word "generate" fits well, but as an option, it may be a bit too broad and could represent the entire process of converting the original meta.js to the meta comment block (both in *.user.js and *.meta.js). I think at least the word "file" should be included to indicate that we are going to generate an extra file. Maybe options.meta.generateFile?

[Giglium]

Changed to options.meta.generateFile it's good! I've also squashed all the commit into one!

[guansss]

Thank you!