exponential-backoff-retry.ts

exponential-backoff-retry.ts

import { Observable, pipe, range, throwError, zip, of, timer } from 'rxjs';
import { map, mergeMap, retryWhen } from 'rxjs/operators';

export const RETRY_COUNT = 3;
export const RETRY_TIME = 500;

export function exponentialBackoffRetry<T>(
	maxTries: number = RETRY_COUNT,
	delay: number = RETRY_TIME,
) {
	return pipe<Observable<T>, Observable<T>>(
		retryWhen(errors => {
			return zip(range(1, maxTries + 1), errors).pipe(
				mergeMap(([i, err]) => (i > maxTries ? throwError(err) : of(i))),
				map(i => i * i), // 1 * 1, 2 * 2...
				mergeMap(v => {
					return timer(v * delay);
				}),
			);
		}),
	);
}