Missing polymorphic behavior (delayWhen) in RxJS 5

[iemejia]

I was trying to create a randomly delayed Observable like this:

"use strict";

var Rx = require('rx');
// var Rx = require('rxjs/Rx');

var source = Rx.Observable.range(0, 100)
    .take(20)
    .delay(x => Rx.Observable.timer(Math.floor(Math.random() * 10000)));

var delayedSubscriber = source.subscribe(
  function (x) { console.log('onNext: %s', x); },
  function (e) { console.log('onError: %s', e); },
  function () { console.log('onCompleted'); }
);

I am not sure if this is the correct way to do what I intend, but I noticed a different behavior when I tested in RxJS 5 and nothing happened. Is it an issue, or did something change in the semantics that I didn't read ?

Thanks.

[kwonoj]

Somewhat yes. As migration guide shows, RxJS5 have separated operator for RxJS4's polymorphic behaved operators. (i.e, debouce & debounceTime). delay also had polymorphic signatures of accepting dateTime and subscriptionDelay with durationSelector, and latter is not added in current codebase yet, so above code snippet does nothing for you.

I remember there was discussion about this at https://github.com/ReactiveX/RxJS/issues/549 and agreed to have delayWhen which has not landed yet.

Does this answer your question? If you'd like to have delayWhen, I can suggest change this issue's subject to request of delayWhen to track its implementation.

[iemejia]

Thanks for answering. I read the migration guide, but as delay was not mentioned in the 'Operator Splits' section I didn't remember it was a polymorphic operator too. I will change the subject and I hope the delayWhen operator gets migrated and added to the guide.

[kwonoj]

delay was not mentioned

Yes, it's missing in guide, I just wanted to pick other examples in guide for separated operators.

[kwonoj]

I'll try to spend some time to make this operator lands in codebase.

[kwonoj]

Closing via https://github.com/ReactiveX/RxJS/pull/1245.

[lock[bot]]

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