feat(doc): move pipe bug

apps/rxjs/pipe-bug/src/app/app.service.ts

@@ -0,0 +1,23 @@
+import { inject, Injectable } from '@angular/core';
+import { merge, mergeMap, Observable, of, take } from 'rxjs';
+import { LocalDBService, TopicType } from './localDB.service';
+
+@Injectable({ providedIn: 'root' })
+export class AppService {
+  private dbService = inject(LocalDBService);
+
+  getAll$ = this.dbService.infos$;
+
+  deleteOldTopics(type: TopicType): Observable<boolean> {
+    return this.dbService.searchByType(type).pipe(
+      take(1),
+      mergeMap((topicToDelete) =>
+        topicToDelete.length > 0
+          ? topicToDelete
+              .map((t) => this.dbService.deleteOneTopic(t.id))
+              .reduce((acc, curr) => merge(acc, curr), of(true))
+          : of(true)
+      )
+    );
+  }
+}