example.js

// current

const [rendered, type] = await (async () => {
  const articleRenderer = new ArticleRenderer();
  const taskRenderer = new TaskRenderer();

  if (doc instanceof Article) {
    return [await articleRenderer.render(doc), 'article'];
  } else if (doc instanceof Task) {
    return [await taskRenderer.render(doc), 'task'];
  } else {
    throw new Error("Unknown doc type");
  }
})();

// future

const [rendered, type] = do {
  const articleRenderer = new ArticleRenderer();
  const taskRenderer = new TaskRenderer();

  if (doc instanceof Article) {
    [await articleRenderer.render(doc), 'article'];
  } else if (doc instanceof Task) {
    [await taskRenderer.render(doc), 'task'];
  } else {
    throw new Error("Unknown doc type");
  }
}