Support for .civet files outputting .svelte.ts/.svelte.js for Svelte Runes reactive compatibility

[adam2am]

Summary

• Expand handling of .civet files to support output extensions like .svelte.ts or .svelte.js.
• Update isCivetTranspiled regex to match .civet.svelte.ts and .civet.svelte.js.
• Update cleanCivetId() to correctly strip new suffixes (.svelte.ts, .svelte.js).
• This enables .civet files to output TypeScript-compatible .svelte files, which are needed for Svelte's new Runes API.
• No breaking changes - .civet.jsx / .civet.tsx are still supported as before.

Motivation

• Svelte's new Runes system.
• Civet users can now fully integrate with workflows by outputting .svelte.ts from .civet files.
  (even tho for now IDE will not recognize syntax of it out of the box, have to manually do .d.ts)

Thanks for reading! 🚀 Happy to adjust anything if needed

[edemaine]

Thanks for this PR, and sorry for the delay. Do you think it would be possible to use outputExtension instead of hard-coding Svelte support? That would be better, I think, but it may require a bit more restructuring.

[adam2am]

Thanks for this PR, and sorry for the delay. Do you think it would be possible to use outputExtension instead of hard-coding Svelte support? That would be better, I think, but it may require a bit more restructuring.

You mean something like this?

  outExt :=
    options.outputExtension ?? (ts is "preserve" ? ".tsx" : ".jsx")
  cleanOutExt := outExt.replace(/\./g, '\\.')
  cleanOutputExtRE := new RegExp(`${cleanOutExt}$`)
  isCivetTranspiled := new RegExp(`(\\.civet)(?:${cleanOutExt})?([?#].*)?$`)

  function cleanCivetId(id: string): {id: string, postfix: string}
    let postfix = ''
    id = id
    .replace postfixRE, (match) =>
      postfix = match
      ''
    .replace cleanOutputExtRE, ''
    {id, postfix}

Also while experimenting I noticed it's adding it to the end, so it's file.civet.ts / file.civet.svelte.ts without stripping
Do you think would it be a cool idea to optionally add something like

   stripCivet  := options.stripCivetExtension ?? false

and some extra logic to make it possible > file.ts / file.svelte.ts / file.tsx or there is no point for doing that?

[edemaine]

If we stick to regular expressions, you'll need to escape all active regexp characters, not just .. (Can't wait for RegExp.escape...) Something like

cleanOutExt := outExt.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')

But I wonder if we could instead just remove do the postfixRE removal, then detect whether the filename endsWIth(outExt), strip that, and then check for /\.civet$/, instead of building a big regular expression.

Do you think would it be a cool idea to optionally add something like

   stripCivet  := options.stripCivetExtension ?? false

I don't think this can work in the unplugin, because we wouldn't be able to detect transformed files, because they no longer have .civet in them. But I'm also not quite sure why it really matters: I don't think the unplugin ever emits a file with the output extension in it, does it? (The CLI already supports writing .ts files instead of .civet.ts files.) I think the unplugin's filenames are all for internal processing purposes. The point of this PR is to allow postprocessing triggered by extensions other than .tsx, including .svelte.ts.

[adam2am]

instead of building a big regular expression.

Hey, sorry for the delay, could you review my code in latest commit is it overcoooked or a nice one

Basically
1 - helper functions instead of regex for validation
2 - splitIdPostfix - only removes ? or # part
3 - validateAndExtractCivetBase -

    - removes postfix
    - checks if id ends with outputextension
    - checks if id before ends with .civet
        true > returns base .civet path, 
        otherwise null

4 - resolveId now uses splitIdPostfix to only remove postfix = path without striping outext, then it appends everything
5 - loadinclude = direct, clear validation (is not null)
6 - load - uses validateAndExtractCivetBase to both validate and extract civet file