Function getCssFilesForChunk

packages/vite/src/node/plugins/html.ts:355–408

(
  chunk: OutputChunk,
  bundle: OutputBundle,
  analyzedImportedCssFiles: Map<OutputChunk, string[]>,
  seenChunks: Set<string> = new Set(),
  seenCss: Set<string> = new Set(),
)

 * correct files when the same chunk is reached via different entry points.
 */
export function getCssFilesForChunk(
  chunk: OutputChunk,
  bundle: OutputBundle,
  analyzedImportedCssFiles: Map<OutputChunk, string[]>,
  seenChunks: Set<string> = new Set(),
  seenCss: Set<string> = new Set(),
): string[] {
  if (seenChunks.has(chunk.fileName)) {
    return []
  }
  seenChunks.add(chunk.fileName)

  if (analyzedImportedCssFiles.has(chunk)) {
    const files = analyzedImportedCssFiles.get(chunk)!
    const additionals = files.filter((file) => !seenCss.has(file))
    additionals.forEach((file) => seenCss.add(file))
    return additionals
  }

  // Collect all CSS from imports (unfiltered for caching, filtered for return)
  const allFiles: string[] = []
  const filteredFiles: string[] = []
  chunk.imports.forEach((file) => {
    const importee = bundle[file]
    if (importee?.type === 'chunk') {
      const importeeCss = getCssFilesForChunk(
        importee,
        bundle,
        analyzedImportedCssFiles,
        seenChunks,
        seenCss,
      )
      filteredFiles.push(...importeeCss)
      // For cache: use the importee's full cached list
      if (analyzedImportedCssFiles.has(importee)) {
        allFiles.push(...analyzedImportedCssFiles.get(importee)!)
      } else {
        allFiles.push(...importeeCss)
      }
    }
  })

  chunk.viteMetadata!.importedCss.forEach((file) => {
    allFiles.push(file)
    if (!seenCss.has(file)) {
      seenCss.add(file)
      filteredFiles.push(file)
    }
  })

  analyzedImportedCssFiles.set(chunk, unique(allFiles))

  return filteredFiles
}

/**
 * Compiles index.html into an entry js module