fix(router): do not finish bootstrap until all the routes are resolved

Fixes angular#12162

modules/@angular/router/src/router.ts

@@ -278,6 +278,18 @@ type NavigationParams = {
   source: NavigationSource,
 };
 
+/**
+ * @internal
+ */
+export type RouterHook = (snapshot: RouterStateSnapshot) => Observable<RouterStateSnapshot>;
+
+/**
+ * @internal
+ */
+function defaultRouterHook(snapshot: RouterStateSnapshot): Observable<RouterStateSnapshot> {
+  return of (snapshot);
+}
+
 
 /**
  * Does not detach any subtrees. Reuses routes as long as their route config is the same.
@@ -320,11 +332,23 @@ export class Router {
    */
   errorHandler: ErrorHandler = defaultErrorHandler;
 
+
+
   /**
    * Indicates if at least one navigation happened.
    */
   navigated: boolean = false;
 
+  /**
+   * Used by RouterModule and experimental libraries. This allows us to
+   * pause the navigation either before preactivation or after it.
+   * @internal
+   */
+  hooks: {beforePreactivation: RouterHook, afterPreactivation: RouterHook} = {
+    beforePreactivation: defaultRouterHook,
+    afterPreactivation: defaultRouterHook
+  };
+
   /**
    * Extracts and merges URLs. Used for AngularJS to Angular migrations.
    */
@@ -679,17 +703,23 @@ export class Router {
         urlAndSnapshot$ = of ({appliedUrl: url, snapshot: precreatedState});
       }
 
+      const beforePreactivationDone$ = mergeMap.call(urlAndSnapshot$, (p: any) => {
+        return map.call(
+            this.hooks.beforePreactivation(p.snapshot),
+            (newSnapshot: any) => ({appliedUrl: p.appliedUrl, snapshot: newSnapshot}));
+      });
 
       // run preactivation: guards and data resolvers
       let preActivation: PreActivation;
-      const preactivationTraverse$ = map.call(urlAndSnapshot$, ({appliedUrl, snapshot}: any) => {
-        preActivation =
-            new PreActivation(snapshot, this.currentRouterState.snapshot, this.injector);
-        preActivation.traverse(this.outletMap);
-        return {appliedUrl, snapshot};
-      });
+      const preactivationTraverse$ =
+          map.call(beforePreactivationDone$, ({appliedUrl, snapshot}: any) => {
+            preActivation =
+                new PreActivation(snapshot, this.currentRouterState.snapshot, this.injector);
+            preActivation.traverse(this.outletMap);
+            return {appliedUrl, snapshot};
+          });
 
-      const preactivationCheckGuards =
+      const preactivationCheckGuards$ =
           mergeMap.call(preactivationTraverse$, ({appliedUrl, snapshot}: any) => {
             if (this.navigationId !== id) return of (false);
 
@@ -698,7 +728,7 @@ export class Router {
             });
           });
 
-      const preactivationResolveData$ = mergeMap.call(preactivationCheckGuards, (p: any) => {
+      const preactivationResolveData$ = mergeMap.call(preactivationCheckGuards$, (p: any) => {
         if (this.navigationId !== id) return of (false);
 
         if (p.shouldActivate) {
@@ -708,11 +738,20 @@ export class Router {
         }
       });
 
+      const preactivationDone$ = mergeMap.call(preactivationResolveData$, (p: any) => {
+        return map.call(
+            this.hooks.afterPreactivation(p.snapshot), (newSnapshot: any) => ({
+                                                         appliedUrl: p.appliedUrl,
+                                                         snapshot: newSnapshot,
+                                                         shouldActivate: p.shouldActivate
+                                                       }));
+      });
+
 
       // create router state
       // this operation has side effects => route state is being affected
       const routerState$ =
-          map.call(preactivationResolveData$, ({appliedUrl, snapshot, shouldActivate}: any) => {
+          map.call(preactivationDone$, ({appliedUrl, snapshot, shouldActivate}: any) => {
             if (shouldActivate) {
               const state =
                   createRouterState(this.routeReuseStrategy, snapshot, this.currentRouterState);

modules/@angular/router/src/router_module.ts

@@ -7,7 +7,8 @@
  */
 
 import {APP_BASE_HREF, HashLocationStrategy, Location, LocationStrategy, PathLocationStrategy, PlatformLocation} from '@angular/common';
-import {ANALYZE_FOR_ENTRY_COMPONENTS, APP_BOOTSTRAP_LISTENER, ApplicationRef, Compiler, ComponentRef, Inject, InjectionToken, Injector, ModuleWithProviders, NgModule, NgModuleFactoryLoader, NgProbeToken, Optional, Provider, SkipSelf, SystemJsNgModuleLoader} from '@angular/core';
+import {ANALYZE_FOR_ENTRY_COMPONENTS, APP_BOOTSTRAP_LISTENER, APP_INITIALIZER, ApplicationRef, Compiler, ComponentRef, Inject, Injectable, InjectionToken, Injector, ModuleWithProviders, NgModule, NgModuleFactoryLoader, NgProbeToken, Optional, Provider, SkipSelf, SystemJsNgModuleLoader} from '@angular/core';
+import {Subject} from 'rxjs';
 
 import {Route, Routes} from './config';
 import {RouterLink, RouterLinkWithHref} from './directives/router_link';
@@ -21,6 +22,7 @@ import {RouterOutletMap} from './router_outlet_map';
 import {NoPreloading, PreloadAllModules, PreloadingStrategy, RouterPreloader} from './router_preloader';
 import {ActivatedRoute} from './router_state';
 import {UrlHandlingStrategy} from './url_handling_strategy';
+import {RouterStateSnapshot} from './router_state';
 import {DefaultUrlSerializer, UrlSerializer} from './url_tree';
 import {flatten} from './utils/collection';
 
@@ -278,22 +280,70 @@ export function rootRoute(router: Router): ActivatedRoute {
   return router.routerState.root;
 }
 
-export function initialRouterNavigation(
-    router: Router, ref: ApplicationRef, preloader: RouterPreloader, opts: ExtraOptions) {
-  return (bootstrappedComponentRef: ComponentRef<any>) => {
+/**
+ * To initialize the router properly we need to do in two steps:
+ *
+ * We need to start the navigation in a APP_INITIALIZER to block the bootstrap if
+ * a resolver or a guards executes asynchronously. Second, we need to actually run
+ * activation in a BOOTSTRAP_LISTENER. We utilize an experimental afterPreactivation
+ * hook provided by the router to do that.
+ *
+ * The router navigation starts, reaches the point when preactivation is done, and then
+ * pauses. It waits for the hook to be resolved. We then resolve it only in a bootstrap listener.
+ */
+@Injectable()
+export class RouterInitializer {
+  private initSnapshot: RouterStateSnapshot;
+  private resultOfPreactivationDone = new Subject<RouterStateSnapshot>();
 
-    if (bootstrappedComponentRef !== ref.components[0]) {
-      return;
-    }
+  constructor(private injector: Injector) {}
+
+  appInitializer(): Promise<any> {
+    let resolve: any = null;
+    const res = new Promise(r => resolve = r);
+
+    const router = this.injector.get(Router);
+
+    router.hooks.afterPreactivation = (s) => {
+      this.initSnapshot = s;
+      resolve(true);
+      return this.resultOfPreactivationDone;
+    };
+
+    const opts = this.injector.get(ROUTER_CONFIGURATION);
 
-    router.resetRootComponentType(ref.componentTypes[0]);
-    preloader.setUpPreloading();
     if (opts.initialNavigation === false) {
       router.setUpLocationChangeListener();
     } else {
       router.initialNavigation();
     }
-  };
+
+    return res;
+  }
+
+  bootstrapListener(bootstrappedComponentRef: ComponentRef<any>): void {
+    const ref = this.injector.get(ApplicationRef);
+    if (bootstrappedComponentRef !== ref.components[0]) {
+      return;
+    }
+
+    const preloader = this.injector.get(RouterPreloader);
+    preloader.setUpPreloading();
+
+    const router = this.injector.get(Router);
+    router.resetRootComponentType(ref.componentTypes[0]);
+
+    this.resultOfPreactivationDone.next(this.initSnapshot);
+    this.resultOfPreactivationDone.complete();
+  }
+}
+
+export function getAppInitializer(r: RouterInitializer) {
+  return r.appInitializer.bind(r);
+}
+
+export function getBootstrapListener(r: RouterInitializer) {
+  return r.bootstrapListener.bind(r);
 }
 
 /**
@@ -306,11 +356,14 @@ export const ROUTER_INITIALIZER =
 
 export function provideRouterInitializer() {
   return [
+    RouterInitializer,
     {
-      provide: ROUTER_INITIALIZER,
-      useFactory: initialRouterNavigation,
-      deps: [Router, ApplicationRef, RouterPreloader, ROUTER_CONFIGURATION]
+      provide: APP_INITIALIZER,
+      multi: true,
+      useFactory: getAppInitializer,
+      deps: [RouterInitializer]
     },
+    {provide: ROUTER_INITIALIZER, useFactory: getBootstrapListener, deps: [RouterInitializer]},
     {provide: APP_BOOTSTRAP_LISTENER, multi: true, useExisting: ROUTER_INITIALIZER},
   ];
 }

modules/@angular/router/test/bootstrap.spec.ts

@@ -0,0 +1,128 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {APP_BASE_HREF} from '@angular/common';
+import {ApplicationRef, CUSTOM_ELEMENTS_SCHEMA, Component, NgModule, destroyPlatform} from '@angular/core';
+import {BrowserModule, DOCUMENT} from '@angular/platform-browser';
+import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
+import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
+import {Resolve, Router, RouterModule} from '@angular/router';
+
+describe('bootstrap should wait for resolvers to complete', () => {
+
+  @Component({selector: 'test-app', template: 'root <router-outlet></router-outlet>'})
+  class RootCmp {
+  }
+
+  @Component({selector: 'test-app2', template: 'root <router-outlet></router-outlet>'})
+  class SecondRootCmp {
+  }
+
+  @Component({selector: 'test', template: 'test'})
+  class TestCmp {
+  }
+
+  class TestResolver implements Resolve<any> {
+    resolve() {
+      let resolve: any = null;
+      const res = new Promise(r => resolve = r);
+      setTimeout(() => resolve('test-data'), 0);
+      return res;
+    }
+  }
+
+  let testProviders: any[] = null;
+
+  beforeEach(() => {
+    destroyPlatform();
+    const fakeDoc = getDOM().createHtmlDocument();
+    const el1 = getDOM().createElement('test-app', fakeDoc);
+    const el2 = getDOM().createElement('test-app2', fakeDoc);
+    getDOM().appendChild(fakeDoc.body, el1);
+    getDOM().appendChild(fakeDoc.body, el2);
+    testProviders =
+        [{provide: DOCUMENT, useValue: fakeDoc}, {provide: APP_BASE_HREF, useValue: ''}];
+  });
+
+  it('should work', (done) => {
+    @NgModule({
+      imports: [
+        BrowserModule,
+        RouterModule.forRoot(
+            [{path: '**', component: TestCmp, resolve: {test: TestResolver}}], {useHash: true})
+      ],
+      declarations: [SecondRootCmp, RootCmp, TestCmp],
+      bootstrap: [RootCmp],
+      providers: [...testProviders, TestResolver],
+      schemas: [CUSTOM_ELEMENTS_SCHEMA]
+    })
+    class TestModule {
+    }
+
+    platformBrowserDynamic([]).bootstrapModule(TestModule).then(res => {
+      const router = res.injector.get(Router);
+      const data = router.routerState.snapshot.root.firstChild.data;
+      expect(data['test']).toEqual('test-data');
+      done();
+    });
+  });
+
+  it('should not init router navigation listeners if a non root component is bootstrapped',
+     (done) => {
+       @NgModule({
+         imports: [BrowserModule, RouterModule.forRoot([], {useHash: true})],
+         declarations: [SecondRootCmp, RootCmp],
+         entryComponents: [SecondRootCmp],
+         bootstrap: [RootCmp],
+         providers: testProviders,
+         schemas: [CUSTOM_ELEMENTS_SCHEMA]
+       })
+       class TestModule {
+       }
+
+       platformBrowserDynamic([]).bootstrapModule(TestModule).then(res => {
+         const router = res.injector.get(Router);
+         spyOn(router, 'resetRootComponentType').and.callThrough();
+
+         const appRef: ApplicationRef = res.injector.get(ApplicationRef);
+         appRef.bootstrap(SecondRootCmp);
+
+         expect(router.resetRootComponentType).not.toHaveBeenCalled();
+
+         done();
+       });
+     });
+
+  it('should reinit router navigation listeners if a previously bootstrapped root component is destroyed',
+     (done) => {
+       @NgModule({
+         imports: [BrowserModule, RouterModule.forRoot([], {useHash: true})],
+         declarations: [SecondRootCmp, RootCmp],
+         entryComponents: [SecondRootCmp],
+         bootstrap: [RootCmp],
+         providers: testProviders,
+         schemas: [CUSTOM_ELEMENTS_SCHEMA]
+       })
+       class TestModule {
+       }
+
+       platformBrowserDynamic([]).bootstrapModule(TestModule).then(res => {
+         const router = res.injector.get(Router);
+         spyOn(router, 'resetRootComponentType').and.callThrough();
+
+         const appRef: ApplicationRef = res.injector.get(ApplicationRef);
+         appRef.components[0].onDestroy(() => {
+           appRef.bootstrap(SecondRootCmp);
+           expect(router.resetRootComponentType).toHaveBeenCalled();
+           done();
+         });
+
+         appRef.components[0].destroy();
+       });
+     });
+});