loadAndTransform() — vite Function Reference

Source Code

packages/vite/src/node/server/transformRequest.ts lines 236–439

async function loadAndTransform(
  environment: DevEnvironment,
  id: string,
  url: string,
  options: TransformOptionsInternal,
  timestamp: number,
  mod?: EnvironmentModuleNode,
  resolved?: PartialResolvedId,
) {
  const { config, pluginContainer, logger } = environment
  const prettyUrl =
    debugLoad || debugTransform ? prettifyUrl(url, config.root) : ''

  const moduleGraph = environment.moduleGraph

  if (options.allowId && !options.allowId(id)) {
    const err: any = new Error(`Denied ID ${id}`)
    err.code = ERR_DENIED_ID
    err.id = id
    throw err
  }

  let code: string | null = null
  let map: SourceDescription['map'] = null
  let moduleType: ModuleType | undefined

  // load
  const loadStart = debugLoad ? performance.now() : 0
  const loadResult = await pluginContainer.load(id)

  if (loadResult == null) {
    const file = cleanUrl(id)

    // try fallback loading it from fs as string
    // if the file is a binary, there should be a plugin that already loaded it
    // as string
    // only try the fallback if access is allowed, skip for out of root url
    // like /service-worker.js or /api/users
    if (
      environment.config.consumer === 'server' ||
      isFileLoadingAllowed(environment.getTopLevelConfig(), slash(file))
    ) {
      try {
        code = await fsp.readFile(file, 'utf-8')
        debugLoad?.(`${timeFrom(loadStart)} [fs] ${prettyUrl}`)
      } catch (e) {
        if (e.code !== 'ENOENT' && e.code !== 'EISDIR') {
          throw e
        }
      }
      if (code != null && environment.pluginContainer.watcher) {
        ensureWatchedFile(
          environment.pluginContainer.watcher,
          file,
          config.root,
        )
      }
    }
    if (code) {
      try {
        const extracted = await extractSourcemapFromFile(code, file)
        if (extracted) {
          code = extracted.code
          map = extracted.map
        }
      } catch (e) {
        logger.warn(`Failed to load source map for ${file}.\n${e}`, {
          timestamp: true,
        })
      }
    }
  } else {
    debugLoad?.(`${timeFrom(loadStart)} [plugin] ${prettyUrl}`)
    if (isObject(loadResult)) {
      code = loadResult.code
      map = loadResult.map
      moduleType = loadResult.moduleType
    } else {
      code = loadResult
    }
  }