(Svelte 5) `svelte-check` fails when project contains only `*.svelte.ts` files

[peterreeves]

Describe the bug

I'm working in a mono-repo using Svelte 5 that has a utils package with only *.svelte.ts files. Running svelte-check --tsconfig ./tsconfig.json fails with the error No svelte input files were found in config file. However adding an empty Thing.svelte file to the package will fix the problem.

Reproduction

https://stackblitz.com/edit/vitejs-vite-gocm7l?file=package.json

Run npm run check and observe the No svelte input files... error.
Create an empty Thing.svelte file in the "src" folder and rerun npm run check.
Observe that svelte-check now runs, and correctly reports the problem in src/my_file.svelte.ts.

Expected behaviour

svelte-check should run even though the package contains no .svelte files.

System Info

• OS: Windows
• IDE: VsCode, StackBlitz

Which package is the issue about?

No response

Additional Information, eg. Screenshots

No response

[jasonlyu123]

Is there any reason why you have to use svelte-check instead of tsc even though there isn't any svelte files?

[peterreeves]

Running vanilla tsc fails because one of the .svelte.ts files uses the $state(...) rune.

[jasonlyu123]

This is becuase run types are ambient types and TypeScirpt isn't aware of it. Once you import anything from svelte, it should be loaded. Or you can create any app.d.ts files with

/// <reference types="svelte" />

[jasonlyu123]

As for the original question, the "no svelte input" error is expected. svelte-check is meant for svelte files so it doesn't make much sense to use svelte-check instead of tsc when you're not dealing with svelte files. svelte-check doesn't have special handling for rune, the only difference is that for typescript to understand svelte files, there is a virtual file generated and the tri slash reference comment mentioned above is in the virtual file.

[peterreeves]

Ahh, ok. Both of those solutions work for me. Thanks for your help!