If something is always loaded, always preload it

[KTibow]

Description

Say I want to load a core part of the app before further features. import makes this easy: I can just split out the further features, import them, and they won't take up space in the core bundle or defer the core code from running. But now I've introduced a waterfall.

Here's a minimal example if you don't get what I mean: https://github.com/KTibow/viterepro

Suggested solution

If something is always going to be loaded, even if through top level import(), always preload it. Maybe extend the same logic used to preload shared chunks.

Alternative

No response

Additional context

I believe this would always be the fastest approach:

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[sapphi-red]

I think it's better to configure output.manualChunks than using import() in top-level.
https://stackblitz.com/edit/github-xeyafyvp?file=src%2Fa.ts
manualChunks is a bit difficult to configure, but Rolldown's advancedChunks should help in the future.

Analyzing whether import() is called in the initial load requires data flow analysis which is not trivial.

[KTibow]

@sapphi-red I get if this isn't easy to implement but that isn't the best workaround - it reverses the order that things are downloaded+ran (c -> b -> a). at that point, you might as well manually use multiple <script> tags.