Revert "fix(router): RouterLinkActive should update its state right after checking the children (#19449)"

This reverts commit c569b75249.
As it was synched together with 5a9ed2de27
which broke an internal test.

packages/router/src/directives/router_link_active.ts

@@ -118,19 +118,21 @@ export class RouterLinkActive implements OnChanges,
 
   private update(): void {
     if (!this.links || !this.linksWithHrefs || !this.router.navigated) return;
-    Promise.resolve().then(() => {
-      const hasActiveLinks = this.hasActiveLinks();
-      if (this.isActive !== hasActiveLinks) {
-        (this as any).isActive = hasActiveLinks;
-        this.classes.forEach((c) => {
-          if (hasActiveLinks) {
-            this.renderer.addClass(this.element.nativeElement, c);
-          } else {
-            this.renderer.removeClass(this.element.nativeElement, c);
-          }
-        });
-      }
-    });
+    const hasActiveLinks = this.hasActiveLinks();
+
+    // react only when status has changed to prevent unnecessary dom updates
+    if (this.isActive !== hasActiveLinks) {
+      this.classes.forEach((c) => {
+        if (hasActiveLinks) {
+          this.renderer.addClass(this.element.nativeElement, c);
+        } else {
+          this.renderer.removeClass(this.element.nativeElement, c);
+        }
+      });
+      Promise.resolve(hasActiveLinks).then(active => (this as{
+                                                       isActive: boolean
+                                                     }).isActive = active);
+    }
   }
 
   private isLinkActive(router: Router): (link: (RouterLink|RouterLinkWithHref)) => boolean {

packages/router/test/integration.spec.ts

@@ -2655,7 +2655,6 @@ describe('Integration', () => {
 
          router.navigateByUrl('/team/22/link;exact=true');
          advance(fixture);
-         advance(fixture);
          expect(location.path()).toEqual('/team/22/link;exact=true');
 
          const nativeLink = fixture.nativeElement.querySelector('a');
@@ -2712,7 +2711,6 @@ describe('Integration', () => {
 
          router.navigateByUrl('/team/22/link;exact=true');
          advance(fixture);
-         advance(fixture);
          expect(location.path()).toEqual('/team/22/link;exact=true');
 
          const native = fixture.nativeElement.querySelector('#link-parent');
@@ -2741,7 +2739,6 @@ describe('Integration', () => {
 
          router.navigateByUrl('/team/22/link');
          advance(fixture);
-         advance(fixture);
          expect(location.path()).toEqual('/team/22/link');
 
          const native = fixture.nativeElement.querySelector('a');

packages/router/test/regression_integration.spec.ts

@@ -7,9 +7,8 @@
  */
 
 import {CommonModule} from '@angular/common';
-import {Component, ContentChild, NgModule, TemplateRef, Type, ViewChild, ViewContainerRef} from '@angular/core';
+import {Component, NgModule, Type} from '@angular/core';
 import {ComponentFixture, TestBed, fakeAsync, tick} from '@angular/core/testing';
-import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {Router} from '@angular/router';
 import {RouterTestingModule} from '@angular/router/testing';
 
@@ -57,56 +56,6 @@ describe('Integration', () => {
          instance.show = true;
          expect(() => advance(fixture)).not.toThrow();
        }));
-
-    it('should set isActive right after looking at its children -- #18983', fakeAsync(() => {
-         @Component({
-           template: `
-          <div #rla="routerLinkActive" routerLinkActive>
-            isActive: {{rla.isActive}}
-            
-            <ng-template let-data>
-              <a [routerLink]="data">link</a>
-            </ng-template>
-
-            <ng-container #container></ng-container>
-          </div>
-        `
-         })
-         class ComponentWithRouterLink {
-           @ViewChild(TemplateRef) templateRef: TemplateRef<any>;
-           @ViewChild('container', {read: ViewContainerRef}) container: ViewContainerRef;
-
-           addLink() {
-             this.container.createEmbeddedView(this.templateRef, {$implicit: '/simple'});
-           }
-
-           removeLink() { this.container.clear(); }
-         }
-
-         @Component({template: 'simple'})
-         class SimpleCmp {
-         }
-
-         TestBed.configureTestingModule({
-           imports: [RouterTestingModule.withRoutes([{path: 'simple', component: SimpleCmp}])],
-           declarations: [ComponentWithRouterLink, SimpleCmp]
-         });
-
-         const router: Router = TestBed.get(Router);
-         const fixture = createRoot(router, ComponentWithRouterLink);
-         router.navigateByUrl('/simple');
-         advance(fixture);
-
-         fixture.componentInstance.addLink();
-         fixture.detectChanges();
-
-         fixture.componentInstance.removeLink();
-         advance(fixture);
-         advance(fixture);
-
-         expect(fixture.nativeElement.innerHTML).toContain('isActive: false');
-       }));
-
   });
 
 });