Unable to make a retry for API call Getting the success event

Question

I am having a requirement to make multiple API calls using fork-join we need to make a retry if any one of the API calls after 3seconds and even then the API is failing then we should not go to subscribe. And the retry should also happen for one time retry that's all For the above requirement, I implemented in the below way:-

const getPosts = this.api
      .get("/posts/")
      .pipe(catchError(this.getCatchError));
    const getPostsFaliure = this.api.get("/postsasdfs/")
      .pipe(catchError(this.getCatchError));
    ;
    forkJoin(getPosts, getPostsFaliure)
      .pipe(
        retryWhen(err => {
          err.pipe(
            tap(val => console.log(`Value ${val} was too high!`)),
            //restart in 6 seconds
            delayWhen(val => timer(val * 1000))
          );
        })
      )
      .subscribe(res => console.log(res));

and getCatcherror is there in this way:-

getCatchError(error) {
    return of(false);
  }

for the above implementation, I am getting the below result:-

[Array(100),false]

it's not going into err and retry is also not working for me API call is going only one time and I need to restrict it going to subscribe until the APIs are passing if at least one is failing I need to go to err part of subscribing. And I am having a strict rule to use retry when from rxjs How to solve this issue

Stackblitz URL:-https://stackblitz.com/edit/angular-api-call-cpr1hk?file=src/app/app.component.ts

Answer 1

You're switching the error to valid notifications with the of(false). It must be removed for the retryWhen to be invoked.

1. You could use an explicit variable to denote the retry attempt.
2. Return either throwError (to forward the error) or EMPTY constant (to complete the observable) from the catchError block.

import { forkJoin, throwError, EMPTY } from 'rxjs';
import { catchError, retryWhen } from 'rxjs/operators';

const getPosts = this.api.get("/posts/");
const getPostsFaliure = this.api.get("/postsasdfs/");
let retry = 0; // max 3 allowed

forkJoin(getPosts, getPostsFaliure).pipe(
  catchError(err => {
    if (retry <= 3) {
      retry++;
      return throwError(err);
    }
    return EMPTY; // <-- complete the observable if max retries reached
  }),
  retryWhen(err => err.pipe(delay(3000)))
).subscribe(res => console.log(res));