fix(router): Ensure Router preloading works with lazy component and static children (#49571)

atscott · atscott · commit 978d37f324ce · 2023-03-24T10:41:11.000-07:00
The preloading strategy did not handle a `loadComponent` on a route with a static `children`. It only preloaded children if they were also `loadChildren` or both were not lazy loaded. fixes #49558 PR Close #49571
diff --git a/packages/router/src/router_preloader.ts b/packages/router/src/router_preloader.ts
@@ -121,7 +121,8 @@ export class RouterPreloader implements OnDestroy {
       if ((route.loadChildren && !route._loadedRoutes && route.canLoad === undefined) ||
           (route.loadComponent && !route._loadedComponent)) {
         res.push(this.preloadConfig(injectorForCurrentRoute, route));
-      } else if (route.children || route._loadedRoutes) {
+      }
+      if (route.children || route._loadedRoutes) {
         res.push(this.processRoutes(injectorForChildren, (route.children ?? route._loadedRoutes)!));
       }
     }
diff --git a/packages/router/test/router_preloader.spec.ts b/packages/router/test/router_preloader.spec.ts
@@ -818,5 +818,35 @@ describe('RouterPreloader', () => {
          tick(3);
          expect(getLoadedComponent(baseRoute)).toBeDefined();
        }));
+
+    it('loads nested components', () => {
+      @Component({template: '', standalone: true})
+      class LoadedComponent {
+      }
+      lazyComponentSpy.and.returnValue(LoadedComponent);
+
+      TestBed.inject(Router).resetConfig([
+        {
+          path: 'a',
+          loadComponent: lazyComponentSpy,
+          children: [{
+            path: 'b',
+            loadComponent: lazyComponentSpy,
+            children: [{
+              path: 'c',
+              loadComponent: lazyComponentSpy,
+              children: [{
+                path: 'd',
+                loadComponent: lazyComponentSpy,
+              }]
+            }]
+          }]
+        },
+      ]);
+
+      const preloader = TestBed.inject(RouterPreloader);
+      preloader.preload().subscribe(() => {});
+      expect(lazyComponentSpy).toHaveBeenCalledTimes(4);
+    });
   });
 });

Original file line number	Diff line number	Diff line change
`@@ -121,7 +121,8 @@ export class RouterPreloader implements OnDestroy {`
`121`	`121`	`if ((route.loadChildren && !route._loadedRoutes && route.canLoad === undefined) \|\|`
`122`	`122`	`(route.loadComponent && !route._loadedComponent)) {`
`123`	`123`	`res.push(this.preloadConfig(injectorForCurrentRoute, route));`
`124`		`- } else if (route.children \|\| route._loadedRoutes) {`
	`124`	`+ }`
	`125`	`+ if (route.children \|\| route._loadedRoutes) {`
`125`	`126`	`res.push(this.processRoutes(injectorForChildren, (route.children ?? route._loadedRoutes)!));`
`126`	`127`	`}`
`127`	`128`	`}`