OK let me correct myself. That's preposterous. You have to `await` a promise to kick off it's process. But my point about being able to assign the promise to a wider-scoped `currentRequestItemPromise` before awaiting it which seems impossible with async iterators, which rejects upon timeout, stands, doesn't it?
On Mon, 31 Jul 2017 at 16:08 Naveen Chawla <[email protected]> wrote: > Yes, you need to intervene and reject the latest promise upon timeout (by > having a reference to its "reject" callback). > > This makes me wonder (and I'd like to be corrected if wrong) if async > iterators are more of a hindrance than a help? > > We can currently do a loop over an array of promises, without async > iterators: > > ```javascript > async requestLoopAsync(){ > for(const requestItemPromise of requestItemPromises){ > //We can intervene here BEFORE we await the promise, unlike > //with async iterators e.g. > requestItemPromise.myRejectCallbackReference() > > const response = await requestItemPromise; //etc. > } > } > ``` > > Am I right or wrong? > > (For the timeout example, we could do `currentRequestItemPromise = > requestItemPromise` then on timeout do > `currentRequestItemPromise.myRejectCallbackReference()` (where > `myRejectCallbackReference` was assigned when we created the promise e.g. > `this.myRejectCallbackReference = reject` from the `reject` parameter in > `(resolve, reject)=>`) > > On Mon, 31 Jul 2017 at 10:40 kai zhu <[email protected]> wrote: > >> the timeout handler will not work as advertised, e.g. what if io / db >> issues causes a network stream to intermittently respond in intervals far >> greater than 30000ms or not at all? >> >> > On Jul 31, 2017, at 7:26 AM, James Browning <[email protected]> >> wrote: >> > >> > It'll look something like this: >> > >> > ```javascript >> > >> > async function consumeReadableStream(stream) { >> > const start = Date.now() >> > for await (const chunk of stream) { >> > >> > /* Do whatever you want with the chunk here e,g, await other >> > async tasks with chunks >> > send them off to wherever, etc >> > */ >> > >> > if (Date.now() - start > 30000) { >> > throw new Error('30000 ms timeout') >> > } >> > } >> > /* Instead of callbackOnce the returned promise from this function >> > itself can be used */ >> > } >> > >> > ``` >> > _______________________________________________ >> > 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 >> >
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