Resolve aliases while running `svelte-kit package`

Describe the problem

Aliases are currently not resolved when packaging since components are only preprocessed.

For example, importing $lib/css/shared.css from $lib/components/Component/SubComponent involves a lot of ../ without aliases. This is very brittle especially considering something like $lib/css/shared.css is something that might be shared across many components at different nested levels.

Describe the proposed solution

It would be helpful if svelte-kit resolved these aliases.

My proposal around Svelte files would be to create a built-in preprocessor that uses plugin-alias since this is already svelte-kit dependency.

It’s not immediately clear what the approach to resolving aliases in js files should be because svelte-kit currently avoids any bundling and just copies them. I haven’t used Typescript, so I don’t know that tsc aliases are compatible with plugin-alias.

Alternatives considered

Not using aliases in any files that will be packaged (my current approach).

Importance

would make my life easier

Additional Information

No response

[dummdidumm]

The $lib alias (no others currently) is now resolved with the caveat that it’s a regexp-based string-replacement, so there might be false positives. Keeping this issue open as this is obviously not the final solution, but it should help for the majority of cases.

[dummdidumm]

In general the package options take priority over the kit options.

I’d be awesome if you implement this, but I fear it either brings some complexity with it or people are confused that they have to configure aliases in multiple places. Right now @sveltejs/package is independent of Vite, so we

• either need to connect it to Vite somehow, which brings complexity into the package
• or keep it indepent, so package.alias would only be concerned with resolving the aliases while bundling, and not make them available as tsconfig paths and/or Vite aliases. This would be easy to implement but might fall short of expectations

I’m not sure what’s the best path forward, so I would like to gather feedback first how people really use @sveltejs/package and if it’s even worth it to add such a feature, given that probably 90% of users will use it in conjunction with SvelteKit, where everything works as expected thanks to you already.