I think the actual answer is that it only works in languages where you can eagerly execute async code disconnected from the Promise/Future construct. It would've worked in ES3 using a Promise polyfill. (Which is notable because it does not fit the aforementioned criteria—it had no real async support.)
It isn’t. The first implementation of promises I worked on was in Java. We used it as part of verifying certificate chains. If you use threads it doesn’t matter if the operations are blocking, as long as you move them off-thread.
jchw|3 years ago
hinkley|3 years ago