feat(getCssExports): adds support for SCSS/SASS partials via aliases

[rmachado-studocu]

What does this PR do:

• Changes getCssExports.ts to try a partial url/path or an _index if newUrl returns undefined.

In practice, with the introduction of tsconfig-paths in #105 led to the requirement that the import line must point to a file in the filesystem.

So if your file is called _colors.scss and you're doing @import './colors'; it would fail...
This PR changes the logic to first test the normal behaviour of searching for a file colors.{sass,scss} ... if it cannot find, then it'll try to prefix the filename with _ and search for _colors.{sass,scss} in the aliases directories...

There was also the request to support index files (see below @lochstar 's comment). After looking at SASS' documentation, I realized that it would make sense to support it, so as a fallback in case it cannot find the partial, it'll try to resolve an index file. Using the above example, if colors is a directory, then it'll search for colors/_index.{sass,scss}.

Attempts to solve #221

[rmachado-studocu]

I hope you're accepting PRs 😄 @mrmckeb

Given it's my first PR here, LMK if something is missing! Thank you for your time reviewing!

[lochstar]

@rmachado-studocu Would this handle _index.scss files as well?

Fails

@use '@src/styles' as *;

Works

@use '@src/styles/_index' as *;

[rmachado-studocu]

@lochstar in the current implementation no.

But I can adapt it to work as such too ... basically if when checking if the _${filename} doesn't exist we can try the _index...

Would it be something you'd like to see implemented?

[lochstar]

@rmachado-studocu Definitely 👍🏻

[rmachado-studocu]

@lochstar I've added the support ... I've also added some tests to verify the changes.

If you try it, LMK if it works for you 👍

[mrmckeb]

Thank you! It looks like you've both tested that this resolves the issues you had, so I'm happy to merge. Thanks!

[mrmckeb]

This has now shipped in v5.1.0. Thanks again!

[lochstar]

Awesome, thanks @rmachado-studocu & @mrmckeb !

[rmachado-studocu]

Thank you @mrmckeb and @lochstar for the reviews 👍