svelte-preprocess

A magical Svelte preprocessor with sensible defaults and support for: PostCSS, SCSS, Less, Stylus, Coffeescript, TypeScript, Pug and much more. Maintained by sveltejs on GitHub, where it has earned 1,797 stars from the community.

It's actively developed around preprocess, svelte, sveltejs, and is a solid reference for anyone building with these tools.