For the first one, it really feels like only a matter of how you break lines. Sure there is also the matter of anonymous function syntax, but The latter is mor

For the first one, it really feels like only a matter of how you break lines. Sure there is also the matter of anonymous function syntax, but The latter is more fair, here is a possible solution: const gen = (function* () { for (let i = 0; i < n; i++) yield a(i); })(); const run = next => !next.done && next.value.then(() => run(gen.next())); run(gen.next()); Or something similar using reduce. But in both cases, it illustrates the point, I guess. But if we are at point we can introduce new keywords/syntax in the language, it would just as well possible to come with something like a.chain(b, c) In case you need to pass parameters a.chain([b, p1, p2], c) And for the latter case const indexes = (function* () { for (let i = 0; i < n; i++) yield i; }) a.through(indexes)