[ACS-8914] Fix error on manage rules page open (#4228)

* [ACS-8914] fix error on manage rules page open

* [ACS-8914] sonar issue

projects/aca-content/folder-rules/src/services/folder-rule-sets.service.spec.ts

@@ -74,6 +74,12 @@ describe('FolderRuleSetsService', () => {
       .and.returnValue(of(getOtherFolderEntryMock));
   });
 
+  it('should have an initial value of null for selectedRuleSet$', async () => {
+    const selectedRuleSetPromise = folderRuleSetsService.selectedRuleSet$.pipe(take(1)).toPromise();
+    const selectedRuleSet = await selectedRuleSetPromise;
+    expect(selectedRuleSet).toBeNull();
+  });
+
   it(`should load node info when loading the node's rule sets`, async () => {
     // take(2), because: 1 = init of the BehaviourSubject, 2 = in subscribe
     const folderInfoPromise = folderRuleSetsService.folderInfo$.pipe(take(2)).toPromise();

projects/aca-content/folder-rules/src/services/folder-rule-sets.service.ts

@@ -24,7 +24,7 @@
 
 import { Injectable } from '@angular/core';
 import { AlfrescoApiService } from '@alfresco/adf-content-services';
-import { BehaviorSubject, combineLatest, from, Observable, of } from 'rxjs';
+import { BehaviorSubject, combineLatest, from, Observable, of, startWith } from 'rxjs';
 import { NodeInfo } from '@alfresco/aca-shared/store';
 import { catchError, finalize, map, switchMap, tap } from 'rxjs/operators';
 import { RuleSet } from '../model/rule-set.model';
@@ -68,20 +68,26 @@ export class FolderRuleSetsService {
   hasMoreRuleSets$: Observable<boolean> = this.hasMoreRuleSetsSource.asObservable();
   folderInfo$: Observable<NodeInfo> = this.folderInfoSource.asObservable();
   isLoading$: Observable<boolean> = this.isLoadingSource.asObservable();
+  selectedRuleSet$: Observable<RuleSet>;
 
-  selectedRuleSet$ = this.folderRulesService.selectedRule$.pipe(
-    map((rule: Rule) => {
-      if (rule === null) {
-        return null;
-      }
-      if (this.mainRuleSet?.rules.findIndex((r: Rule) => r.id === rule.id) > -1) {
-        return this.mainRuleSet;
-      }
-      return this.inheritedRuleSets.find((ruleSet: RuleSet) => ruleSet.rules.findIndex((r: Rule) => r.id === rule.id) > -1) ?? null;
-    })
-  );
-
-  constructor(private apiService: AlfrescoApiService, private contentApi: ContentApiService, private folderRulesService: FolderRulesService) {}
+  constructor(
+    private readonly apiService: AlfrescoApiService,
+    private readonly contentApi: ContentApiService,
+    private readonly folderRulesService: FolderRulesService
+  ) {
+    this.selectedRuleSet$ = this.folderRulesService.selectedRule$.pipe(
+      startWith(null),
+      map((rule: Rule) => {
+        if (rule === null) {
+          return null;
+        }
+        if (this.mainRuleSet?.rules.findIndex((r: Rule) => r.id === rule.id) > -1) {
+          return this.mainRuleSet;
+        }
+        return this.inheritedRuleSets.find((ruleSet: RuleSet) => ruleSet.rules.findIndex((r: Rule) => r.id === rule.id) > -1) ?? null;
+      })
+    );
+  }
 
   private callApi(path: string, httpMethod: string, body: object = {}): Promise<any> {
     // APIs used by this service are still private and not yet available for public use