IMO that's an explicitly different issue than a comparison between Promises/async/await and Ruby's metaprogramming, though. Not to mention that part of the iss

IMO that's an explicitly different issue than a comparison between Promises/async/await and Ruby's metaprogramming, though. Not to mention that part of the issue with Promises is the various polyfills invented before broad acceptance, which is a separate can of worms, and a different type of complexity than the (relatively) heavy use of metaprogramming in Ruby (relative to JS).