Cannot find any of modules: sass,node-sass

Describe the bug

The same as #622, but I can not get over it.

To Reproduce

I didn’t use svelte-preprocess and/or svelte.config.js. I’m using the @sveltejs/vite-plugin-svelte and let vite handle the preprocessing through useVitePreprocess option.

In fact, this plugin works well and vite does not complain about it. But vscode does not think so, it throws error on <style lang="scss"> tag about not founding “sass” or “node-sass” package.

I’ve created a reproduction repo: https://github.com/hyrious/vite-svelte-sass-bug.

I have tried these steps but no luck:

• add svelte.language-server.runtime option
• install sass both in the project and in global

Expected behavior

The extension should be able to find the sass module.

Screenshots

System (please complete the following information):

• OS: macOS 12.0.1
• IDE: VSCode
• Plugin/Package: Svelte for VSCode, svelte-language-server

Additional context

[dummdidumm]

I’m very hesitant to add any other dependencies solely for preprocessor diagnostics. Right now Less and SASS seem like a good addition, but with the rise of TailwindCSS people might expect something there, too, and over time it could become too bloated, and removing already added stuff is then somewhat of a breaking change. Therefore I’d like to keep this to TypeScript-only for now. Maybe we should instead switch how we deal with these diagnostic errors?

• Option 1: ignore errors that come from missing modules if there’s no svelte.config.js
• Option 2: same as option 1 but print a warning with more explanation instead. For svelte-check, this could be a one-time when it’s first encountered to not clutter up diagnostics.

What do others think about this?

[jasonlyu123]

@Lucide That’s unrelated to this issue. In your case, You need a svelte.config.js as the language server also need to know how to preprocess. And we can’t read the config passed into rollup-plugin-svelte in your rollup config.