Include styles for dynamically imported components

[Rich-Harris]

#5137. This is a partial fix — it solves the SSR problem in prod builds, and solves it in dev when the page is reloaded (because node.ssrTransformResult has been computed by that point), but not for the initial page load. Not yet sure what the solution looks like. Maybe we can wait until load has completed before computing the styles. (The most obvious alternative is to eagerly load the dynamically imported modules, but that would be a bad idea in the case where they're dynamically imported precisely because they can't be loaded on the server.)

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[benmccann]

It might be nice to see if we can use Vite's importedCss (vitejs/vite#6629)

[dominikg]

maybe related: injecting a link for component styles is pending this: sveltejs/vite-plugin-svelte#341

If we want to avoid the js, is there a way to compile only the css for a component?

[PatrickG]

Can we merge this as is so that styles of dynamic imported components load at least in production builds without javascript?

[Rich-Harris]

It might be nice to see if we can use Vite's importedCss (vitejs/vite#6629)

Not sure I understand what that is and what benefit it brings?

If we want to avoid the js, is there a way to compile only the css for a component?

Not without changes to Svelte itself

Can we merge this as is so that styles of dynamic imported components load at least in production builds without javascript?

We generally try and avoid that — it ends up being more work as you need to create a new issue and then (eventually) a new PR. Better to just fix it in one go, even if it means a slight delay

[Rich-Harris]

Alright, I think this is ready to go