refactor(css): use preliminaryFileName to detect pure CSS chunks (#…

…13974)

packages/vite/src/node/plugins/css.ts

@@ -38,7 +38,6 @@ import type { ResolvedConfig } from '../config'
 import type { Plugin } from '../plugin'
 import {
   arraify,
-  arrayEqual,
   asyncReplace,
   cleanUrl,
   combineSourcemaps,
@@ -735,21 +734,17 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
       // remove empty css chunks and their imports
       if (pureCssChunks.size) {
         // map each pure css chunk (rendered chunk) to it's corresponding bundle
-        // chunk. we check that by comparing the `moduleIds` as they have different
-        // filenames (rendered chunk has the !~{XXX}~ placeholder)
-        const pureCssChunkNames: string[] = []
-        for (const pureCssChunk of pureCssChunks) {
-          for (const key in bundle) {
-            const bundleChunk = bundle[key]
-            if (
-              bundleChunk.type === 'chunk' &&
-              arrayEqual(bundleChunk.moduleIds, pureCssChunk.moduleIds)
-            ) {
-              pureCssChunkNames.push(key)
-              break
-            }
-          }
-        }
+        // chunk. we check that by `preliminaryFileName` as they have different
+        // `filename`s (rendered chunk has the !~{XXX}~ placeholder)
+        const prelimaryNameToChunkMap = Object.fromEntries(
+          Object.values(bundle)
+            .filter((chunk): chunk is OutputChunk => chunk.type === 'chunk')
+            .map((chunk) => [chunk.preliminaryFileName, chunk.fileName]),
+        )
+
+        const pureCssChunkNames = [...pureCssChunks].map(
+          (pureCssChunk) => prelimaryNameToChunkMap[pureCssChunk.fileName],
+        )
 
         const emptyChunkFiles = pureCssChunkNames
           .map((file) => path.basename(file))