Function prepareRolldownOptimizerRun

packages/vite/src/node/optimizer/index.ts:770–885

(
  environment: Environment,
  depsInfo: Record<string, OptimizedDepInfo>,
  processingCacheDir: string,
  optimizerContext: { cancelled: boolean },
)

}

async function prepareRolldownOptimizerRun(
  environment: Environment,
  depsInfo: Record<string, OptimizedDepInfo>,
  processingCacheDir: string,
  optimizerContext: { cancelled: boolean },
): Promise<{
  context?: { build: () => Promise<RolldownOutput>; cancel: () => void }
  idToExports: Record<string, ExportsData>
}> {
  // esbuild generates nested directory output with lowest common ancestor base
  // this is unpredictable and makes it difficult to analyze entry / output
  // mapping. So what we do here is:
  // 1. flatten all ids to eliminate slash
  // 2. in the plugin, read the entry ourselves as virtual files to retain the
  //    path.
  const flatIdDeps: Record<string, string> = {}
  const idToExports: Record<string, ExportsData> = {}

  const { optimizeDeps } = environment.config

  const { plugins: pluginsFromConfig = [], ...rolldownOptions } =
    optimizeDeps.rolldownOptions ?? {}

  let jsxLoader = false
  await Promise.all(
    Object.keys(depsInfo).map(async (id) => {
      const src = depsInfo[id].src!
      const exportsData = await (depsInfo[id].exportsData ??
        extractExportsData(environment, src))
      if (exportsData.jsxLoader) {
        // Ensure that optimization won't fail by defaulting '.js' to the JSX parser.
        // This is useful for packages such as Gatsby.
        jsxLoader = true
      }
      const flatId = flattenId(id)
      flatIdDeps[flatId] = isWindows ? src.replaceAll('/', '\\') : src
      idToExports[id] = exportsData
    }),
  )

  if (optimizerContext.cancelled) return { context: undefined, idToExports }

  const define = {
    'process.env.NODE_ENV': environment.config.keepProcessEnv
      ? // define process.env.NODE_ENV even for keepProcessEnv === true
        // as esbuild will replace it automatically when `platform` is `'browser'`
        'process.env.NODE_ENV'
      : JSON.stringify(process.env.NODE_ENV || environment.config.mode),
    ...rolldownOptions.transform?.define,
  }

  const platform =
    optimizeDeps.rolldownOptions?.platform ??
    // We generally don't want to use platform 'neutral', as esbuild has custom handling
    // when the platform is 'node' or 'browser' that can't be emulated by using mainFields
    // and conditions
    (environment.config.consumer === 'client' ||
    environment.config.ssr.target === 'webworker'