Rewriting _renderUniversal

index.ts

// in index.ts, simplify
async function _renderUniversal(
  routes: string[],
  context: BuilderContext,
  clientPath: string,
  serverPath: string,
  indexFile: string
): Promise<BuilderOutput> {

  // the server bundle is server/main.js
  const serverBundlePath = path.join(serverPath, 'main.js');

  // no more loop into outputPaths
  if (!fs.existsSync(serverBundlePath)) {
    throw new Error(`Could not find the main bundle: ${serverBundlePath}`);
  }
  context.logger.info(`Prerendering ${routes.length} route(s) to ${clientPath}...`);

 try {
   // reduced the two tries into one
   // this map is alright, I'll keep it
   const results = (await Promise.all(
      routes.map((route) => {
        // removed deployUrl, and assume css related props
        const options: RenderOptions = {
          indexFile,
          clientPath, // this is outputPath
          route,
          serverBundlePath
        };
        // direct import from worker, no more Piscina worker
        return PreRender(options);
      })
    )) as RenderResult[];
    let numErrors = 0;
    for (const { errors, warnings } of results) {
      errors?.forEach((e) => context.logger.error(e));
      warnings?.forEach((e) => context.logger.warn(e));
      numErrors += errors?.length ?? 0;
    }
    if (numErrors > 0) {
      throw Error(`Rendering failed with ${numErrors} worker errors.`);
    }
    context.logger.info(`Prerendering routes to ${clientPath} complete.`);

  } catch (err) {
    context.logger.error(`Prerendering routes to ${clientPath} failed.`);
    return { success: false, error: err.message };
  }
  return { success: true};
}