🐛 Type imports in Svelte files are not detected when using svelte compiler

[arnolicious]

Prerequisites

• I'm using the latest version
• I've read the relevant documentation
• I've searched for existing issues
• I've checked the list of known issues
• I've read the issue reproduction guide

Reproduction url

https://github.com/arnolicious/knip-compiler-types-repro

Reproduction access

• I've made sure the reproduction is publicly accessible

Description of the issue

When using knip with the "real" svelte compiler, knip fails to detect types that are imported in svelte files.

When not using the "real" svelte compiler, knip detects the types just fine, but then fails to detect svelte specific features, such as dynamic component imports.

I assume the solution is to somehow configure / patch the compile step to also include types, however I wouldn't really know where to start.

Unfortunately in this state, this makes it very difficult to use knip in a large sveltekit project

[webpro]

The basic idea is to set compilers: { svelte: input => output } ) where input is the Svelte source file string, and output is the TypeScript source file string containing the imports and exports. Perhaps an approach could be to copy functions/regexes from Knip source code and adjust to your needs, e.g. also include dynamic component imports.

Happy to help and/or review a pull request with improved svelte "compiler" in Knip.

[webpro]

Also see https://knip.dev/features/compilers#svelte

[arnolicious]

Sorry, just to make sure I understand correctly, you'd suggest adjusting the built-in knip svelte compiler to also include things like dynamic imports, rather than using the real svelte compiler like described in https://knip.dev/features/compilers#svelte ?

Or would there be a way to extend the compile step, to use the real compiler, and additionally handle keeping the type imports/exports?

I'm not very familiar with how knip works under the hood, so sorry for misunderstanding how things might work

[webpro]

Sorry, just to make sure I understand correctly, you'd suggest adjusting the built-in knip svelte compiler to also include things like dynamic imports [..]

Yes.

By "copy" I meant you could suit yourself by configuring your own compiler. If you set compilers.svelte then that function overrides the built-in one. Feel free to base that on Knip source code.

And if you would go that route, I'm interested in that and happy to review a pull request to improve Knip for others as well. No pressure on that one, though.

Or would there be a way to extend the compile step, to use the real compiler, and additionally handle keeping the type imports/exports?

Not sure about that, depends on what the real Svelte compiler does. I heard it strips types?