Function exportAppImpl

packages/next/src/export/index.ts:191–1045

(
  dir: string,
  options: Readonly<ExportAppOptions>,
  span: Span,
  staticWorker?: StaticWorker
)

}

async function exportAppImpl(
  dir: string,
  options: Readonly<ExportAppOptions>,
  span: Span,
  staticWorker?: StaticWorker
): Promise<ExportAppResult | null> {
  dir = resolve(dir)

  // attempt to load global env values so they are available in next.config.js
  span.traceChild('load-dotenv').traceFn(() => loadEnvConfig(dir, false, Log))

  const { enabledDirectories } = options

  const nextConfig =
    options.nextConfig ||
    (await span.traceChild('load-next-config').traceAsyncFn(() =>
      loadConfig(PHASE_EXPORT, dir, {
        debugPrerender: options.debugPrerender,
      })
    ))

  const distDir = join(dir, nextConfig.distDir)
  const telemetry = options.buildExport ? null : new Telemetry({ distDir })

  if (telemetry) {
    telemetry.record(
      eventCliSession(nextConfig, {
        webpackVersion: null,
        cliCommand: 'export',
        isSrcDir: null,
        hasNowJson: !!(await findUp('now.json', { cwd: dir })),
        isCustomServer: null,
        turboFlag: false,
        pagesDir: null,
        appDir: null,
      })
    )
  }

  const subFolders = nextConfig.trailingSlash && !options.buildExport

  if (!options.silent && !options.buildExport) {
    Log.info(`using build directory: ${distDir}`)
  }

  const buildIdFile = join(distDir, BUILD_ID_FILE)

  if (!existsSync(buildIdFile)) {
    throw new ExportError(
      `Could not find a production build in the '${distDir}' directory. Try building your app with 'next build' before starting the static export. https://nextjs.org/docs/messages/next-export-no-build-id`
    )
  }

  const customRoutes = (['rewrites', 'redirects', 'headers'] as const).filter(
    (config) => typeof nextConfig[config] === 'function'
  )

  if (!hasNextSupport && !options.buildExport && customRoutes.length > 0) {