Export a component from a larger SvelteKit project

Describe the problem

It should be possible to export a single Component as a .js file with inlined CSS. This is super useful for building micro-frontends. With sveltes new capability to attach to a shadow-dom, single components can be exported and be used in another app by ether calling new Component(...) or by using svelte:fragment.

Currently this can only be achieved by using a separate rollup config.

Describe the proposed solution

Just another key in the config to describe which files should be exported and in which format.
Example svelte.config.js:

...
const config = {
    ...
    external: [
       {
            input: 'lib/Example.svelte',
            output: 'external/Example.js',
           format: 'iife'
       }
    ]
    ...
}
...

Alternatives considered

Use vites library mode. Currently this leads to the error "UMD and IIFE output formats are not supported for code-splitting builds."

Importance

would make my life easier

Additional Information

No response

Start by reviewing the svelte.config.js configuration and the current Rollup/Vite build behavior, including the library-mode code-splitting limitation. Define how component inputs, output paths, formats, and inlined CSS should be represented, then verify that a single component can be consumed as the requested JavaScript output.