Handle more complex SASS/SCSS syntax

[babakness]

Is your feature request related to a problem? Please describe.

Yes, the css incompatible parts of sass don't seem to be supported.

It would be great if we could write with programmatic short hand like this in SASS

@for $section from 1 to 10 {
  .section-#{$section} {
    // something systematic
  }
} 

and get typings for the compiled CSS result

.section-1 { ... }
.section-2 { ... }
.section-3 { ... }

Describe the solution you'd like
SASS/SCSS files are compiled for full SASS pre-processor language support

Describe alternatives you've considered
n/a

[babakness]

My naive approach was to try to compile SASS files to CSS before classes are extracted. However, the compilation process using render on both node-sass and sass are asynchronous (require a callback). The first obvious step was to promisify them and use asyc/away functions. Alas, it does not appear that the function used by TS can return a promise.

typescript-plugin-css-modules/src/index.ts

Line 19 in 769366a

ts.createLanguageServiceSourceFile = (

BTW, I tried using renderSync on both node-sass and sass and they both seem to crash the language server in VS Code.

I also tried a couple different postcss-sass plugins, didn't seem to work either.

Thoughts

Perhaps the author, @mrmckeb, is aware of how to turn a fully rendered SASS files to CSS then extract classes within the restrictions of a VS Code plugin.

[babakness]

For now, I've made a package to compile sass into type definitions for use in projects

https://github.com/babakness/sass-module-types

[mrmckeb]

Thanks @babakness, sorry for the slow response - I've had a busy week...

This has been a hard exercise for me too, as there obviously needs to be a balance between feature support and speed of compilation... the more features supported, the slower updates will be - which impacts TypeScript's performance too.

I'm not entirely sure what the best path forward is here. I'm currently working on something for Create React App, which is eating my open source time, but could look at this in 2 weeks or so.

That module looks cool, I'll definitely reference it when adding improvements here.

[hellocontrol-bng]

+1 on this, especially because using those complex features actually prevents the rest of the file from working as expected. I have a file that breaks because it uses a mixin, and the result is that NONE of the classes in that file are reflected, even if they are not using the mixin at all.

[DavidBabel]

Your both libs are awesome guys. You can make a pretty neat thing if you guys work together ;)

[mrmckeb]

Closed by #20. Will be released later today :)