Options to (de)select page in lookup search results made available co…

…nditionally

- Emit a result list even if no items are found (result list of 0 items)
- The "Select page" and "Deselect page" drop-down options in the search results list are disabled if there are zero items in the result list

Fixes: #3312

src/app/shared/form/builder/ds-dynamic-form-ui/relation-lookup-modal/dynamic-lookup-relation-modal.component.spec.ts

@@ -193,13 +193,15 @@ describe('DsDynamicLookupRelationModalComponent', () => {
       spyOn((component as any).store, 'dispatch');
     });
 
-    it('should dispatch an AddRelationshipAction for each selected object', () => {
-      component.select(searchResult1, searchResult2);
+    it('should dispatch an AddRelationshipAction for each (valid) selected object', () => {
+      component.select(searchResult1, undefined, searchResult2);
       const action = new AddRelationshipAction(component.item, searchResult1.indexableObject, relationship.relationshipType, submissionId, nameVariant);
       const action2 = new AddRelationshipAction(component.item, searchResult2.indexableObject, relationship.relationshipType, submissionId, nameVariant);
 
       expect((component as any).store.dispatch).toHaveBeenCalledWith(action);
       expect((component as any).store.dispatch).toHaveBeenCalledWith(action2);
+      expect((component as any).store.dispatch).not.toHaveBeenCalledWith(undefined);
+      expect((component as any).store.dispatch).toHaveBeenCalledTimes(2);
     });
   });
 
@@ -210,13 +212,15 @@ describe('DsDynamicLookupRelationModalComponent', () => {
       spyOn((component as any).store, 'dispatch');
     });
 
-    it('should dispatch an RemoveRelationshipAction for each deselected object', () => {
-      component.deselect(searchResult1, searchResult2);
+    it('should dispatch an RemoveRelationshipAction for each (valid) deselected object', () => {
+      component.deselect(searchResult1, undefined, searchResult2);
       const action = new RemoveRelationshipAction(component.item, searchResult1.indexableObject, relationship.relationshipType, submissionId);
       const action2 = new RemoveRelationshipAction(component.item, searchResult2.indexableObject, relationship.relationshipType, submissionId);
 
       expect((component as any).store.dispatch).toHaveBeenCalledWith(action);
       expect((component as any).store.dispatch).toHaveBeenCalledWith(action2);
+      expect((component as any).store.dispatch).not.toHaveBeenCalledWith(undefined);
+      expect((component as any).store.dispatch).toHaveBeenCalledTimes(2);
     });
   });
 

src/app/shared/form/builder/ds-dynamic-form-ui/relation-lookup-modal/dynamic-lookup-relation-modal.component.ts

@@ -291,7 +291,7 @@ export class DsDynamicLookupRelationModalComponent implements OnInit, OnDestroy
   select(...selectableObjects: SearchResult<DSpaceObject>[]) {
     this.zone.runOutsideAngular(
       () => {
-        const obs: Observable<any[]> = observableCombineLatest([...selectableObjects.map((sri: SearchResult<Item>) => {
+        const obs: Observable<any[]> = observableCombineLatest([...selectableObjects.filter((object: SearchResult<DSpaceObject>) => object).map((sri: SearchResult<Item>) => {
           this.addNameVariantSubscription(sri);
           return this.relationshipService.getNameVariant(this.listId, sri.indexableObject.uuid)
             .pipe(
@@ -333,7 +333,7 @@ export class DsDynamicLookupRelationModalComponent implements OnInit, OnDestroy
    */
   deselect(...selectableObjects: SearchResult<DSpaceObject>[]) {
     this.zone.runOutsideAngular(
-      () => selectableObjects.forEach((object) => {
+      () => selectableObjects.filter((object: SearchResult<DSpaceObject>) => object).forEach((object) => {
         this.subMap[object.indexableObject.uuid].unsubscribe();
         this.store.dispatch(new RemoveRelationshipAction(this.item, object.indexableObject as Item, this.relationshipOptions.relationshipType, this.submissionId));
       }),

src/app/shared/form/builder/ds-dynamic-form-ui/relation-lookup-modal/search-tab/dynamic-lookup-relation-search-tab.component.html

@@ -33,8 +33,10 @@
         </button>
         <div ngbDropdownMenu aria-labelledby="resultdropdown" *ngVar="(resultsRD$ | async) as resultsRD">
           <button class="dropdown-item"
+                  [disabled]="resultsRD?.page.length === 0"
                   (click)="selectPage(resultsRD?.page)">{{ ('submission.sections.describe.relationship-lookup.search-tab.select-page' | translate) }}</button>
           <button class="dropdown-item"
+                  [disabled]="resultsRD?.page.length === 0"
                   (click)="deselectPage(resultsRD?.page)">{{ ('submission.sections.describe.relationship-lookup.search-tab.deselect-page' | translate) }}</button>
         </div>
       </div>

src/app/shared/form/builder/ds-dynamic-form-ui/relation-lookup-modal/search-tab/dynamic-lookup-relation-search-tab.component.ts

@@ -220,7 +220,9 @@ export class DsDynamicLookupRelationSearchTabComponent implements OnInit, OnDest
       .pipe(take(1))
       .subscribe((selection: SearchResult<Item>[]) => {
         const filteredPage: SearchResult<DSpaceObject>[] = page.filter((pageItem: SearchResult<DSpaceObject>) => selection.findIndex((selected: SearchResult<Item>) => selected.equals(pageItem)) < 0);
-        this.selectObject.emit(...filteredPage);
+        if (filteredPage && filteredPage.length > 0) {
+          this.selectObject.emit(...filteredPage);
+        }
       });
     this.selectableListService.select(this.listId, page);
   }
@@ -235,7 +237,9 @@ export class DsDynamicLookupRelationSearchTabComponent implements OnInit, OnDest
       .pipe(take(1))
       .subscribe((selection: SearchResult<Item>[]) => {
         const filteredPage = page.filter((pageItem) => selection.findIndex((selected) => selected.equals(pageItem)) >= 0);
-        this.deselectObject.emit(...filteredPage);
+        if (filteredPage && filteredPage.length > 0) {
+          this.deselectObject.emit(...filteredPage);
+        }
       });
     this.selectableListService.deselect(this.listId, page);
   }
@@ -260,7 +264,9 @@ export class DsDynamicLookupRelationSearchTabComponent implements OnInit, OnDest
         take(1),
         tap((selection: SearchResult<Item>[]) => {
           const filteredResults = results.filter((pageItem) => selection.findIndex((selected) => selected.equals(pageItem)) < 0);
-          this.selectObject.emit(...filteredResults);
+          if (filteredResults && filteredResults.length > 0) {
+            this.selectObject.emit(...filteredResults);
+          }
         }),
         mapTo(results),
       )),

src/app/shared/search/search.component.ts

@@ -540,9 +540,7 @@ export class SearchComponent implements OnDestroy, OnInit {
           if (this.trackStatistics) {
             this.service.trackSearch(searchOptionsWithHidden, results.payload);
           }
-          if (results.payload?.page?.length > 0) {
-            this.resultFound.emit(results.payload);
-          }
+          this.resultFound.emit(results.payload);
         }
         this.resultsRD$.next(results);
       });