Support tsconfig option in svelte2tsx emitDts

[quentinderoubaix]

Context

When working in a monorepository, it is possible to end up with the following structure:

• package-a
  • tsconfig.json
• package-b ➡️ depends on package-a
  • tsconfig.json ➡️ uses compiler path option to target the sources of package-a
  • tsconfig.build.json ➡️ no compiler path option

This allows a few things:

• when checking any source file of package-b in your favorite IDE, navigating to a reference of package-a would open the source file, not the dist file
• in the script commands of package-b, svelte-package and svelte-check can use tsconfig.build.json to make sure package-a is not re-transpiled

Issue

This is almost possible currently, as svelte-package supports a tsconfig option. However, the function emitDts from svelte2tsx does not support an input tsconfig path, so this results in unexpected behavior.

A reproduction repo to see the issue in action:
https://github.com/quentinderoubaix/showcase-tsconfig/tree/main

Proposed solution

Allow an extra option tsconfig in emitDts of package svelte2tsx + update svelte-package in svelte-kit to use it.

Alternatives

No response

Additional Information, eg. Screenshots

If this issue is deemed valid, I would be down to contribute in both this repo and kit to handle it.

[dummdidumm]

Sorry for the late reply - this makes total sense, contributions welcome!

[quentinderoubaix]

Tracking stuff to do:

• add tsconfig option in emitDts
• pass through the tsconfig option in svelte-package