Enabling preserved CSS modules in output

[kirkobyte]

It would be great to allow preserving modules in the CSS output by this tool.

In the case of building a design system, it can be good to leave it up to consuming applications to bundle CSS so they can tree-shake and code-split as their app requires. E.g. if a user was to import Component from a design system, they wouldn't also want the CSS from Component2, so separate CSS files could be useful.

src/
├── components
│   ├── Component
│   │  ├ index.tsx
│   │  └ index.css.ts
│   └── // ...
└── // ...

dist/
├── components
│   ├── Component
│   │  ├ index.js
│   │  └ index.css
│   └── // ...
└── // ...

In a previous discussion around supporting other bundlers in this repo, it was stated that Rollup may not be a good target for vanilla-extract at this point because it doesn't have first-class CSS bundling support:

Just an update on the Rollup integration work—since it doesn’t have first class CSS bundling support, we're thinking it’s probably not a good target for static extraction.

If this use-case is something Vanilla Extract would like to support, either enabling support for Rollup with preserveModules: true or adding support for preserving separate CSS modules in the ESBuild plugin could be really promising

[Piero87]

I'm looking for an answer about this topic too