fix: Move CSS collection to generateBundle for Vite 6 & 7 compatibility

[dc-riskhub]

Problem

In Vite 6 & 7, chunk.viteMetadata.importedCss is not populated when the renderChunk hook runs. This causes the CSS map to be empty, resulting in micro-frontend CSS not being loaded in production.

Root Cause

The plugin currently collects CSS in the renderChunk hook, but Vite 6/7 only populates viteMetadata.importedCss after all renderChunk hooks have completed. When the plugin checks for CSS files, the metadata is still empty.

Solution

Move CSS collection from the renderChunk hook to the generateBundle hook, where viteMetadata.importedCss is fully populated.

Changes

• Removed CSS collection logic from renderChunk hook
• Added CSS collection logic to generateBundle hook before injecting the cssMap
• Added defensive null checks for importedCss and imports arrays
• Added explanatory comment about Vite 7 compatibility

Testing

Verified with a monorepo containing 7+ micro-frontends on Vite 7.2.7:

Before fix:

cssInjectedDictionary="{\"main\":[]}"

After fix:

cssInjectedDictionary="{\"main\":[\"assets/vpss(@riskhub/actions-man)main-xxx.css\"]}"

All micro-frontend CSS now loads correctly in production builds.

Related

This issue was mentioned in #87 where the workaround was to use inlineDynamicImports: true. This fix resolves the root cause, allowing proper code splitting while maintaining CSS loading.

[webJose]

Does it work in Vite v6 as well?

[dc-riskhub]

I've not had the chance to test it in Vite 6, but I when I get a spare moment, I'll do so and report back.

[dc-riskhub]

@webJose I tested in Vite 6.4.1 and can confirm it works. This fix relies on Rollup's hook execution order, which doesn't change across these versions of Vite. This means the CSS map is populated properly in both Vite 6 and 7. 👍

Also pushed a fix for the map tests too.

[webJose]

Thanks for testing. My PC fried and i had to buy a new one. I should get it today. In the meantime i'm using a tablet but I cannot add trusted publishing to the repo with it. Must wait for the new hardware.

[dc-riskhub]

My pleasure, sorry to hear your machine went kaput. If there are any other changes you'd like me to consider, do let me know.

Many thanks!