Yup, thanks! What's the story for modern browsers that don't yet support those features? Do they both have polyfills?
As I mentioned in the article, libraries and futures aren't exclusive to Dart. It's just that they are here now for Dart and are compiled to JavaScript for all modern browsers.
I think it's telling that the original author didn't use Promises or Modules. Of course he could have, but we should ask, why didn't he?