repeat-4.ts

import { repeat } from 'rxjs';

@Injectable({ providedIn: 'root' })
export class MetricsService {
  private http = inject(HttpClient);

  getMetrics() {
    return this.http.get('https://metrics')
      .pipe(
        repeat({ delay: 30_000 }),
        // 👇
        retry(3),
        // 👇
        retry({
          count: 3,
          delay: 1000
        }),
        // 👇
        retry({
          count: 3,
          delay: (error, count) => {
           // Retry forever, but with an exponential step-back
           // maxing out at 1 minute.
           return timer(Math.min(60000, 2 ^ count * 1000))
          },
        })
      )
  }
}

Thanks for a great example (as always), it helped me migrate from retryWhen()!

However, I believe you have a small error on line 24. The ^ operator is bitwise XOR (I think), and you should use Math.pow() instead.
It threw me off looking into this, so I guess it could confuse others as well :-)