Function runOptimizeDeps

packages/vite/src/node/optimizer/index.ts:520–768

(
  environment: Environment,
  depsInfo: Record<string, OptimizedDepInfo>,
)

 * the metadata and start the server without waiting for the optimizeDeps processing to be completed
 */
export function runOptimizeDeps(
  environment: Environment,
  depsInfo: Record<string, OptimizedDepInfo>,
): {
  cancel: () => Promise<void>
  result: Promise<DepOptimizationResult>
} {
  const optimizerContext = { cancelled: false }

  const depsCacheDir = getDepsCacheDir(environment)
  const processingCacheDir = getProcessingDepsCacheDir(environment)

  // Create a temporary directory so we don't need to delete optimized deps
  // until they have been processed. This also avoids leaving the deps cache
  // directory in a corrupted state if there is an error
  fs.mkdirSync(processingCacheDir, { recursive: true })

  // a hint for Node.js
  // all files in the cache directory should be recognized as ES modules
  debug?.(colors.green(`creating package.json in ${processingCacheDir}`))
  fs.writeFileSync(
    path.resolve(processingCacheDir, 'package.json'),
    `{\n  "type": "module"\n}\n`,
  )

  const metadata = initDepsOptimizerMetadata(environment)

  metadata.browserHash = getOptimizedBrowserHash(
    metadata.hash,
    depsFromOptimizedDepInfo(depsInfo),
  )

  // We prebundle dependencies with esbuild and cache them, but there is no need
  // to wait here. Code that needs to access the cached deps needs to await
  // the optimizedDepInfo.processing promise for each dep

  const qualifiedIds = Object.keys(depsInfo)
  let cleaned = false
  let committed = false
  const cleanUp = () => {
    // If commit was already called, ignore the clean up even if a cancel was requested
    // This minimizes the chances of leaving the deps cache in a corrupted state
    if (!cleaned && !committed) {
      cleaned = true
      // No need to wait, we can clean up in the background because temp folders
      // are unique per run
      debug?.(colors.green(`removing cache dir ${processingCacheDir}`))
      try {
        // When exiting the process, `fsp.rm` may not take effect, so we use `fs.rmSync`
        fs.rmSync(processingCacheDir, { recursive: true, force: true })
      } catch {
        // Ignore errors
      }
    }
  }

  const successfulResult: DepOptimizationResult = {
    metadata,