fix backoff on server error

src/lib/error/server-error-interceptor.ts

@@ -1,7 +1,7 @@
 import { HttpErrorResponse, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest, HttpStatusCode } from '@angular/common/http';
 import { Inject, Injectable, Optional } from '@angular/core';
-import { MonoTypeOperatorFunction, Observable, pipe, retry, throwError, timer } from 'rxjs';
+import { MonoTypeOperatorFunction, Observable, retry, throwError, timer } from 'rxjs';
-import { catchError, mergeMap, tap } from 'rxjs/operators';
+import { catchError, tap } from 'rxjs/operators';
 import { MAX_RETRIES_ON_SERVER_ERROR } from './max-retries.token';
 import { ErrorService } from './error.service';
 import { KeycloakService } from 'keycloak-angular';
@@ -16,19 +16,19 @@ function updateSeconds(seconds: number) {
 
 function backoffOnServerError(maxRetries = 3): MonoTypeOperatorFunction<HttpEvent<unknown>> {
     let seconds = 0;
-    const timerExpiration = pipe(
-        tap<HttpErrorResponse>(() => (seconds = updateSeconds(seconds))),
-        mergeMap((error: HttpErrorResponse, index) => {
-            if ((error.status < HttpStatusCode.InternalServerError && error.status !== 0) || index === maxRetries) {
-                return throwError(() => error);
-            }
 
-            console.error('An error occurred: ', error);
+    function delay(error: HttpErrorResponse) {
-            console.error(`Retrying in ${seconds} seconds...`);
+        seconds = updateSeconds(seconds);
-            return timer(seconds * 1000);
+        if (error.status < HttpStatusCode.InternalServerError && error.status !== 0) {
-        }),
+            return throwError(() => error);
-    );
+        }
-    return retry({ delay: (errors: Observable<HttpErrorResponse>) => errors.pipe(timerExpiration) });
+
+        console.error('An error occurred: ', error);
+        console.error(`Retrying in ${seconds} seconds...`);
+        return timer(seconds * 1000);
+    }
+
+    return retry({ count: maxRetries, delay });
 }
 
 @Injectable()