so that everyday programmers can relate, can someone give a code-snippet of the
proposal equivalent to the common-use nodejs example below?
```javascript
function consumeReadableStream(stream, consumeChunk, callback) {
/*
* stream - readable stream
* consumeChunk - has signature - function (chunk) {...}
* callback - has signature - function (error) {...}
*/
var callbackOnce, done, timerTimeout;
callbackOnce = function (error) {
/*
* this function will ensure callback is called only once
*/
if (done) {
return;
}
done = true;
// clear timeout
clearTimeout(timerTimeout);
callback(error);
};
// init timeout handler
timerTimeout = setTimeout(function () {
callbackOnce(new Error('30000 ms timeout'));
stream.destroy();
}, 30000);
stream.on('data', consumeChunk);
stream.on('end', callbackOnce);
stream.on('error', callbackOnce);
};
```
> On Jul 30, 2017, at 2:16 PM, Naveen Chawla <[email protected]> wrote:
>
> Guys!
>
> I thought of a way of doing this. Roughly it's having 2 loops, one for
> consumer and one for requester. Would this work?:
>
> ```
> startRequestingAsync();
> startConsumingAsync();
>
> async startRequestingAsync(){
> for async (const item of requestItems){
> //Control the requesting. Do nothing to actually consume the data
> }
> }
>
> async startConsumingAsync(){
> for async(const item of requestItems){
> //Consume the item. Here you can also apply "front pressure" to
> request the next item if the "request" loop is behind
> }
> }
> ```
>
> I haven't actually done this so it's just thinking out loud.
>
> Thoughts?
>
> On Sun, 30 Jul 2017 at 03:59 Isiah Meadows <[email protected]
> <mailto:[email protected]>> wrote:
> There's also this strawman of mine which deals with most things async, but it
> has several of its own issues that I haven't quite addressed (complexity
> still being one after a week straight):
>
> https://github.com/isiahmeadows/non-linear-proposal
> <https://github.com/isiahmeadows/non-linear-proposal>
> I will caution that async iteration and observation can't really be merged
> meaningfully as you would hope. They both represent multiple values over
> time, but one is eager, the other lazy.
>
>
> On Sat, Jul 29, 2017, 06:54 Naveen Chawla <[email protected]
> <mailto:[email protected]>> wrote:
> Interesting!!!
>
> Excuse my ignorance, but with this construct, how would you trivially invoke
> a "publish" ahead of any given "consumption"?
>
> As far as I can see,
>
> ```
> for await (const item of requestItems){
>
> }
> ```
> on its own is purely a "front-pressure" construct. That is, each request is
> made upon the completion and satisfactory consumption of the last one.
>
> Can you suggest a way to trivially invoke some "back pressure" using this
> construct? By this I mean - invoke extra requests before they come to be
> consumed (like you can do with reactive streaming libraries). An example use
> would be if you wanted to do some "eager loading" of data while the user is
> likely to be viewing but not currently interacting with existing content, for
> example.
>
> You seem very familiar with this construct, so I wouldn't be surprised if
> you've already thought about this! (If you're too busy I'm sure there are
> others here familiar with it too!)
>
> On Tue, 11 Jul 2017 at 21:09 Domenic Denicola <[email protected]
> <mailto:[email protected]>> wrote:
> https://github.com/tc39/proposal-async-iteration
> <https://github.com/tc39/proposal-async-iteration>
>
>
> From: es-discuss [mailto:[email protected]
> <mailto:[email protected]>] On Behalf Of Naveen Chawla
> Sent: Tuesday, July 11, 2017 09:24
> To: [email protected] <mailto:[email protected]>
> Subject: Stream + async await
>
>
>
> It'd be great to have async stream constructs such as:
> http://reactivex.io/rxjs/ <http://reactivex.io/rxjs/> , supported natively,
> such that they can be used directly with the async / await keywords for async
> stream programming in a linear fashion (analogous to what can already be done
> with linearly awaiting Promises, but for async streams instead).
>
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