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 Angular 1 to Angular 2 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 +7,9 @@
  */
 
 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 {RouterStateSnapshot} from '@angular/router';
+import {Observable, Subject} from 'rxjs';
 
 import {Route, Routes} from './config';
 import {RouterLink, RouterLinkWithHref} from './directives/router_link';
@@ -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},
   ];
 }