Function bundleWorkerEntry

packages/vite/src/node/plugins/worker.ts:162–306

(
  config: ResolvedConfig,
  id: string,
)

const workerOutputCaches = new WeakMap<ResolvedConfig, WorkerOutputCache>()

async function bundleWorkerEntry(
  config: ResolvedConfig,
  id: string,
): Promise<WorkerBundle> {
  const input = cleanUrl(id)

  const workerOutput = workerOutputCaches.get(config.mainConfig || config)!
  workerOutput.removeBundleIfInvalidated(input)

  const bundleInfo = workerOutput.getWorkerBundle(input)
  if (bundleInfo) {
    return bundleInfo
  }

  const newBundleChain = [...config.bundleChain, input]
  if (config.bundleChain.includes(input)) {
    throw new Error(
      'Circular worker imports detected. Vite does not support it. ' +
        `Import chain: ${newBundleChain.map((id) => prettifyUrl(id, config.root)).join(' -> ')}`,
    )
  }

  // bundle the file as entry to support imports
  const { rolldown } = await import('rolldown')
  const { plugins, rolldownOptions, format } = config.worker
  const workerConfig = await plugins(newBundleChain)
  const workerEnvironment = new BuildEnvironment('client', workerConfig) // TODO: should this be 'worker'?
  await workerEnvironment.init()

  const chunkMetadataMap = new ChunkMetadataMap()
  const workerBuildTarget = workerEnvironment.config.build.target
  const bundle = await rolldown({
    ...rolldownOptions,
    input,
    plugins: workerEnvironment.plugins.map((p) =>
      injectEnvironmentToHooks(workerEnvironment, chunkMetadataMap, p),
    ),
    onLog(level, log) {
      onRollupLog(level, log, workerEnvironment)
    },
    transform: {
      target: workerBuildTarget === false ? undefined : workerBuildTarget,
      ...rolldownOptions.transform,
      define: {
        ...rolldownOptions.transform?.define,
        // disable builtin process.env.NODE_ENV replacement as it is handled by the define plugin
        'process.env.NODE_ENV': 'process.env.NODE_ENV',
      },
    },
    // TODO: remove this and enable rolldown's CSS support later
    moduleTypes: {
      '.css': 'js',
      ...rolldownOptions.moduleTypes,
    },
    preserveEntrySignatures: false,
    experimental: {
      ...rolldownOptions.experimental,
      viteMode: true,