108555: Refactored ItemSelectComponent to not call canSelect every time changes are detected

src/app/shared/object-select/item-select/item-select.component.html

@@ -17,17 +17,17 @@
         </tr>
         </thead>
         <tbody>
-        <tr *ngFor="let item of itemsRD?.payload?.page">
+        <tr *ngFor="let selectItem of selectItems$ | async">
-          <td><input [disabled]="!(canSelect(item) | async)" class="item-checkbox" [ngModel]="getSelected(item.id) | async" (change)="switch(item.id)" type="checkbox" name="{{item.id}}"></td>
+          <td><input [disabled]="(selectItem.canSelect$ | async) === false" class="item-checkbox" [ngModel]="selectItem.selected$ | async" (change)="switch(selectItem.dso.id)" type="checkbox" name="{{selectItem.dso.id}}"></td>
           <td *ngIf="!hideCollection">
-            <span *ngVar="(item.owningCollection | async)?.payload as collection">
+            <span *ngVar="(selectItem.dso.owningCollection | async)?.payload as collection">
               <a *ngIf="collection" [routerLink]="['/collections', collection?.id]">
                 {{ dsoNameService.getName(collection) }}
               </a>
             </span>
           </td>
-          <td><span *ngIf="item.hasMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])">{{item.firstMetadataValue(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])}}</span></td>
+          <td><span *ngIf="selectItem.dso.hasMetadata(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])">{{selectItem.dso.firstMetadataValue(['dc.contributor.author', 'dc.creator', 'dc.contributor.*'])}}</span></td>
-          <td><a [routerLink]="[(itemPageRoutes$ | async)[item.id]]">{{ dsoNameService.getName(item) }}</a></td>
+          <td><a [routerLink]="selectItem.route">{{ dsoNameService.getName(selectItem.dso) }}</a></td>
         </tr>
         </tbody>
       </table>

src/app/shared/object-select/item-select/item-select.component.spec.ts

@@ -184,15 +184,16 @@ describe('ItemSelectComponent', () => {
     beforeEach(() => {
       comp.featureId = FeatureID.CanManageMappings;
       spyOn(authorizationDataService, 'isAuthorized').and.returnValue(of(false));
+      comp.ngOnInit();
     });
 
-    it('should disable the checkbox', waitForAsync(() => {
+    it('should disable the checkbox', waitForAsync(async () => {
       fixture.detectChanges();
-      fixture.whenStable().then(() => {
+      await fixture.whenStable();
-        const checkbox = fixture.debugElement.query(By.css('input.item-checkbox')).nativeElement;
+
-        expect(authorizationDataService.isAuthorized).toHaveBeenCalled();
+      const checkbox = fixture.debugElement.query(By.css('input.item-checkbox')).nativeElement;
-        expect(checkbox.disabled).toBeTrue();
+      expect(authorizationDataService.isAuthorized).toHaveBeenCalled();
-      });
+      expect(checkbox.disabled).toBeTrue();
     }));
   });
 });

src/app/shared/object-select/item-select/item-select.component.ts

@@ -1,14 +1,13 @@
-import { Component, Input } from '@angular/core';
+import { Component, Input, OnInit } from '@angular/core';
 import { Item } from '../../../core/shared/item.model';
-import { ObjectSelectService } from '../object-select.service';
 import { ObjectSelectComponent } from '../object-select/object-select.component';
 import { hasValueOperator, isNotEmpty } from '../../empty.util';
 import { Observable } from 'rxjs';
 import { getAllSucceededRemoteDataPayload } from '../../../core/shared/operators';
 import { map } from 'rxjs/operators';
 import { getItemPageRoute } from '../../../item-page/item-page-routing-paths';
-import { AuthorizationDataService } from '../../../core/data/feature-authorization/authorization-data.service';
+import { PaginatedList } from '../../../core/data/paginated-list.model';
-import { DSONameService } from '../../../core/breadcrumbs/dso-name.service';
+import { DSpaceObjectSelect } from '../object-select.model';
 
 @Component({
   selector: 'ds-item-select',
@@ -18,7 +17,7 @@ import { DSONameService } from '../../../core/breadcrumbs/dso-name.service';
 /**
  * A component used to select items from a specific list and returning the UUIDs of the selected items
  */
-export class ItemSelectComponent extends ObjectSelectComponent<Item> {
+export class ItemSelectComponent extends ObjectSelectComponent<Item> implements OnInit {
 
   /**
    * Whether or not to hide the collection column
@@ -27,35 +26,25 @@ export class ItemSelectComponent extends ObjectSelectComponent<Item> {
   hideCollection = false;
 
   /**
-   * The routes to the items their pages
+   * Collection of all the data that is used to display the {@link Item} in the HTML.
-   * Key: Item ID
+   * By collecting this data here it doesn't need to be recalculated on evey change detection.
-   * Value: Route to item page
    */
-  itemPageRoutes$: Observable<{
+  selectItems$: Observable<DSpaceObjectSelect<Item>[]>;
-    [itemId: string]: string
-  }>;
-
-  constructor(
-    protected objectSelectService: ObjectSelectService,
-    protected authorizationService: AuthorizationDataService,
-    public dsoNameService: DSONameService,
-  ) {
-    super(objectSelectService, authorizationService);
-  }
 
   ngOnInit(): void {
     super.ngOnInit();
     if (!isNotEmpty(this.confirmButton)) {
       this.confirmButton = 'item.select.confirm';
     }
-    this.itemPageRoutes$ = this.dsoRD$.pipe(
+    this.selectItems$ = this.dsoRD$.pipe(
       hasValueOperator(),
       getAllSucceededRemoteDataPayload(),
-      map((items) => {
+      map((items: PaginatedList<Item>) => items.page.map((item: Item) => Object.assign(new DSpaceObjectSelect<Item>(), {
-        const itemPageRoutes = {};
+        dso: item,
-        items.page.forEach((item) => itemPageRoutes[item.uuid] = getItemPageRoute(item));
+        canSelect$: this.canSelect(item),
-        return itemPageRoutes;
+        selected$: this.getSelected(item.id),
-      })
+        route: getItemPageRoute(item),
+      } as DSpaceObjectSelect<Item>))),
     );
   }
 

src/app/shared/object-select/object-select.model.ts

@@ -0,0 +1,29 @@
+import { Observable } from 'rxjs';
+import { DSpaceObject } from '../../core/shared/dspace-object.model';
+
+/**
+ * Class used to collect all the data that that is used by the {@link ObjectSelectComponent} in the HTML.
+ */
+export class DSpaceObjectSelect<T extends DSpaceObject> {
+
+  /**
+   * The {@link DSpaceObject} to display
+   */
+  dso: T;
+
+  /**
+   * Whether the {@link DSpaceObject} can be selected
+   */
+  canSelect$: Observable<boolean>;
+
+  /**
+   * Whether the {@link DSpaceObject} is selected
+   */
+  selected$: Observable<boolean>;
+
+  /**
+   * The {@link DSpaceObject}'s route
+   */
+  route: string;
+
+}

src/app/shared/object-select/object-select/object-select.component.ts

@@ -9,6 +9,7 @@ import { SortOptions } from '../../../core/cache/models/sort-options.model';
 import { FeatureID } from '../../../core/data/feature-authorization/feature-id';
 import { AuthorizationDataService } from '../../../core/data/feature-authorization/authorization-data.service';
 import { DSpaceObject } from '../../../core/shared/dspace-object.model';
+import { DSONameService } from '../../../core/breadcrumbs/dso-name.service';
 
 /**
  * An abstract component used to select DSpaceObjects from a specific list and returning the UUIDs of the selected DSpaceObjects
@@ -17,7 +18,7 @@ import { DSpaceObject } from '../../../core/shared/dspace-object.model';
   selector: 'ds-object-select-abstract',
   template: ''
 })
-export abstract class ObjectSelectComponent<TDomain> implements OnInit, OnDestroy {
+export abstract class ObjectSelectComponent<TDomain extends DSpaceObject> implements OnInit, OnDestroy {
 
   /**
    * A unique key used for the object select service
@@ -88,8 +89,11 @@ export abstract class ObjectSelectComponent<TDomain> implements OnInit, OnDestro
    */
   selectedIds$: Observable<string[]>;
 
-  constructor(protected objectSelectService: ObjectSelectService,
+  constructor(
-              protected authorizationService: AuthorizationDataService) {
+    protected objectSelectService: ObjectSelectService,
+    protected authorizationService: AuthorizationDataService,
+    public dsoNameService: DSONameService,
+  ) {
   }
 
   ngOnInit(): void {