What problem does this feature solve?

Currently, Rolldown supports bundling CSS, but it always outputs the CSS file separately from the bundle.

It would simplify many things, if we could only get a single file output (js or html).

There are many Rollup plugins that provide this functionality already:

• https://www.npmjs.com/package/rollup-plugin-styles
• https://www.npmjs.com/package/rollup-plugin-bundle-inject
• https://www.npmjs.com/package/rollup-plugin-import-css

This feature is also supported on Rsbuild/Rspack.

What does the proposed API look like?

Proposed API:

Having an inlineCSS option on output. Similar to the already existing inlineDynamicImports.