[wip] @snowpack/plugin-sass & @snowpack/plugin-postcss

[drwpow]

Adds 2 new plugins for handling Sass & PostCSS. 💅

WIP because it’s currently blocked by:

1. Release of Snowpack w/ updated plugin API
2. Re-adding the original file location on disk for plugins to use (Sass needs this to resolve relative imports).

[drwpow]

I’m actually pretty 👎 on node-sass. Particularly with it having some pretty fundamental issues like these:

• Does node-sass support @use, and @forward? sass/node-sass#2886
• rgb and rgba functions misinterpret CSS variables as a single value instead of their output sass/node-sass#2251

For those not familiar, this is VERY different than Dart Sass (the default Sass CLI). It’s essentially a major version behind, and has some pretty big bugs. 🤔 I’m wondering if there’s a way to use Dart Sass’ CLI somehow in this plugin. That would certainly make this plugin not only more usable and bug-free, but possibly faster, too.

[piotr-cz]

I've never used sass, but it looks like postcss may be extended to use it: https://www.postcss.parts/tag/sass

[drwpow]

it looks like postcss may be extended to use it: https://www.postcss.parts/tag/sass

Ah sorry—missed this comment. PostCSS can understand Sass syntax through a number of plugins, but it can’t compile it. So unfortunately, we currently do need to run both Sass + PostCSS together (though somewhat annoying, it’s a common pattern the Sass community is used to and is the default way of doing things).