On August 20, 2018 1:46:45 AM GMT+02:00, Gus Caplan <[email protected]> wrote: >If you use for-await syntax, the js implementation will internally use >GetIterator[1] which will look for Symbol.asyncIterator and if it can't >find it it will return an async wrapper around Symbol.iterator -Gus
Would be nice to have something like Reflect.getAsyncIteratorOf(...), then. Or AsyncIterator.of(...), if something like AsyncIterator exists. That would do the wrapping of sync ones as well. >[1]: https://tc39.github.io/ecma262/#sec-getiterator ---- On Sun, 19 >Aug 2018 16:34:27 -0500 Herbert Vojčík <[email protected]> wrote ---- >Hello! Lately, I created this in one project: export async function* >zip (...iterables) { for (const iterators = iterables.map(each => >(each[Symbol.iterator] || each[Symbol.asyncIterator]).apply(each)); ;) >{ const all = await Promise.all(iterators.map(async each => await >each.next())); if (all.some(each => each.done)) break; yield >all.map(each => each.value); } } It was sync generator before, but once >one of the entries became async generator, I changed the zip itself to >be async. My question is to the pretty ugly const iterators = >iterables.map(each => (each[Symbol.iterator] || >each[Symbol.asyncIterator]).apply(each)) Is there some more idiomatic >way to find "any iterator; sync or async" / alternatively, could sync >iterator return respective [[asyncIterator]] as well, just promisifying >the result (as a sort of proto-proposal of sort)? Or is there some easy >way to change sync iterable to async iterable, so I could change the >other ones at call site? Thanks, Herby >_______________________________________________ es-discuss mailing list >[email protected] https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
