fix(NativeScriptPlatformRef): Destroy lastModuleRef on exitEvent

nativescript-angular/platform-common.ts

@@ -33,6 +33,8 @@ import {
     on,
     launchEvent,
     LaunchEventData,
+    exitEvent,
+    ApplicationEventData,
 } from "tns-core-modules/application";
 import { TextView } from "tns-core-modules/ui/text-view";
 
@@ -255,7 +257,29 @@ export class NativeScriptPlatformRef extends PlatformRef {
                 args.root = rootContent;
             }
         );
+        const exitCallback = profile(
+            "nativescript-angular/platform-common.exitCallback", (args: ApplicationEventData) => {
+                const androidActivity = args.android;
+                if (androidActivity && !androidActivity.isFinishing()) {
+                    // Exit event was triggered as a part of a restart of the app.
+                    return;
+                }
+
+                const lastModuleRef = lastBootstrappedModule ? lastBootstrappedModule.get() : null;
+                if (lastModuleRef) {
+                    // Make sure the module is only destroyed once
+                    lastBootstrappedModule = null;
+
+                    lastModuleRef.destroy();
+                }
+
+                if (!autoCreateFrame) {
+                    rootContent = null;
+                }
+            }
+        );
         on(launchEvent, launchCallback);
+        on(exitEvent, exitCallback);
 
         applicationRun();
     }

nativescript-angular/router/page-router-outlet.ts

@@ -352,12 +352,19 @@ export class PageRouterOutlet implements OnDestroy { // tslint:disable-line:dire
         // Add it to the new page
         page.content = componentView;
 
-        page.on(Page.navigatedFromEvent, (<any>global).Zone.current.wrap((args: NavigatedData) => {
+        const navigatedFromCallback = (<any>global).Zone.current.wrap((args: NavigatedData) => {
             if (args.isBackNavigation) {
                 this.locationStrategy._beginBackPageNavigation(this.frame);
                 this.locationStrategy.back(null, this.frame);
             }
-        }));
+        });
+        page.on(Page.navigatedFromEvent, navigatedFromCallback);
+        componentRef.onDestroy(() => {
+            if (page) {
+                page.off(Page.navigatedFromEvent, navigatedFromCallback);
+                page = null;
+            }
+        });
 
         const navOptions = this.locationStrategy._beginPageNavigation(this.frame);
 
@@ -367,14 +374,15 @@ export class PageRouterOutlet implements OnDestroy { // tslint:disable-line:dire
                 if (this.outlet) {
                     this.routeReuseStrategy.clearCache(this.outlet.outletKeys[0]);
                 }
-                page.off(Page.navigatedToEvent, clearCallback);
             });
 
-            page.on(Page.navigatedToEvent, clearCallback);
+            page.once(Page.navigatedToEvent, clearCallback);
         }
 
         this.frame.navigate({
-            create: () => { return page; },
+            create() {
+                return page;
+            },
             clearHistory: navOptions.clearHistory,
             animated: navOptions.animated,
             transition: navOptions.transition