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Rxjs Retry with Delay function

I am trying to use retry with delay function, I expect function will call after 1000ms delay, but it doesnot, what can be error here? look at console output, it is same time 16:22:48.

I expect there 16:22:48, 16:22:59 ...

canCreate: boolean; getSomeFunction(): Observable<boolean> {         return new Observable<boolean>(             observer => {                 const canCreate = null; // this is just null for now, will some value later                 if (canCreate == null) {                     observer.error('error');                 } else {                     observer.next(true);                 }                 observer.complete();             }         )     }   this.getSomeFunction()       .do((value) => {         this.cCreate = value;       }, (error) => {          console.log(error + new Date().toTimeString());       })       .delay(1000)       .retry(10)       .subscribe(         value => this.cCreate = value,         error => {           this.cCreate = false;         },         () => {}       );   } 

and console result is :

enter image description here

like image 451
Mujah Maskey Avatar asked Jul 07 '17 20:07

Mujah Maskey


Video Answer


1 Answers

delay() is used to introduce a delay between events emitted by the observable. But the observable never emits any event. It just errors immediately.

What you're looking for is retryWhen(), which allows deciding after how long to retry:

RxJS 5:

  .retryWhen(errors => errors.delay(1000).take(10)) 

RxJS 6:

import { retryWhen, delay, take } from 'rxjs/operators' someFunction().pipe(   // ...   retryWhen(errors => errors.pipe(delay(1000), take(10))) ) 

This will complete the whole observable after 10 attempts. If you want to error the whole observable after 10 attempts, the observable returned by the retryWhen callback must throw:

RxJS 5:

  .retryWhen(errors => errors.delay(1000).take(10).concat(Observable.throw())) 

RxJS 6:

import { retryWhen, delay, take, concatMap, throwError } from 'rxjs/operators' someFunction().pipe(   // ...   retryWhen(errors => errors.pipe(delay(1000), take(10), concatMap(throwError))) ) 
like image 190
JB Nizet Avatar answered Sep 23 '22 00:09

JB Nizet