From df76a2048b92c2cb977fcc6d884a898c712e5068 Mon Sep 17 00:00:00 2001
From: Alexander Vologin <alecvolo@gmail.com>
Date: Wed, 16 Jan 2019 04:09:03 -0500
Subject: [PATCH] fix(router): restore 'history.state' object for navigations
 coming from Angular router (#28108) (#28176)

When navigations coming from Angular router we may have a payload stored in state property. When this
 exists, set extras's state to the payload.

PR Close #28176
---
 packages/router/src/router.ts            | 10 ++++-
 packages/router/test/integration.spec.ts | 53 ++++++++++++++++++++++++
 2 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/packages/router/src/router.ts b/packages/router/src/router.ts
index 83b915fa3c..a4e1dae9fa 100644
--- a/packages/router/src/router.ts
+++ b/packages/router/src/router.ts
@@ -920,7 +920,15 @@ export class Router {
           // hybrid apps.
           setTimeout(() => {
             const {source, state, urlTree} = currentChange;
-            this.scheduleNavigation(urlTree, source, state, {replaceUrl: true});
+            const extras: NavigationExtras = {replaceUrl: true};
+            if (state) {
+              const stateCopy = {...state};
+              delete stateCopy.navigationId;
+              if (Object.keys(stateCopy).length !== 0) {
+                extras.state = stateCopy;
+              }
+            }
+            this.scheduleNavigation(urlTree, source, state, extras);
           }, 0);
         }
         this.lastLocationChangeInfo = currentChange;
diff --git a/packages/router/test/integration.spec.ts b/packages/router/test/integration.spec.ts
index ce343becea..47d4edbbce 100644
--- a/packages/router/test/integration.spec.ts
+++ b/packages/router/test/integration.spec.ts
@@ -159,6 +159,59 @@ describe('Integration', () => {
          expect(navigation.extras.state).toEqual({foo: 'bar'});
        })));
 
+    it('should set history.state when navigation with browser back and forward',
+       fakeAsync(inject([Router, Location], (router: Router, location: SpyLocation) => {
+         router.resetConfig([
+           {path: '', component: SimpleCmp},
+           {path: 'simple', component: SimpleCmp},
+         ]);
+
+         const fixture = createRoot(router, RootCmp);
+         let navigation: Navigation = null!;
+         router.events.subscribe(e => {
+           if (e instanceof NavigationStart) {
+             navigation = <Navigation>router.getCurrentNavigation()!;
+           }
+         });
+
+         const state = {foo: 'bar'};
+         router.navigateByUrl('/simple', {state});
+         tick();
+         location.back();
+         tick();
+         location.forward();
+         tick();
+
+         expect(navigation.extras.state).toBeDefined();
+         expect(navigation.extras.state).toEqual(state);
+       })));
+
+    it('should not error if state is not {[key: string]: any}',
+       fakeAsync(inject([Router, Location], (router: Router, location: SpyLocation) => {
+         router.resetConfig([
+           {path: '', component: SimpleCmp},
+           {path: 'simple', component: SimpleCmp},
+         ]);
+
+         const fixture = createRoot(router, RootCmp);
+         let navigation: Navigation = null!;
+         router.events.subscribe(e => {
+           if (e instanceof NavigationStart) {
+             navigation = <Navigation>router.getCurrentNavigation()!;
+           }
+         });
+
+         location.replaceState('', '', 42);
+         router.navigateByUrl('/simple');
+         tick();
+         location.back();
+         advance(fixture);
+
+         // Angular does not support restoring state to the primitive.
+         expect(navigation.extras.state).toEqual(undefined);
+         expect(location.getState()).toEqual({navigationId: 3});
+       })));
+
     it('should not pollute browser history when replaceUrl is set to true',
        fakeAsync(inject([Router, Location], (router: Router, location: SpyLocation) => {
          router.resetConfig([