custom route reuse strategy (#515)

src/app/app.module.ts

@@ -25,7 +25,7 @@
 
 import { BrowserModule } from '@angular/platform-browser';
 import { NgModule } from '@angular/core';
-import { RouterModule } from '@angular/router';
+import { RouterModule, RouteReuseStrategy } from '@angular/router';
 import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
 import { FormsModule, ReactiveFormsModule } from '@angular/forms';
 import { TRANSLATION_PROVIDER, CoreModule, AppConfigService, DebugAppConfigService } from '@alfresco/adf-core';
@@ -83,6 +83,7 @@ import { SearchResultsRowComponent } from './components/search/search-results-ro
 import { NodePermissionsDialogComponent } from './dialogs/node-permissions/node-permissions.dialog';
 import { NodePermissionsDirective } from './directives/node-permissions.directive';
 import { PermissionsManagerComponent } from './components/permission-manager/permissions-manager.component';
+import { AppRouteReuseStrategy } from './app.routes.strategy';
 
 @NgModule({
     imports: [
@@ -143,6 +144,7 @@ import { PermissionsManagerComponent } from './components/permission-manager/per
         ExperimentalDirective
     ],
     providers: [
+        { provide: RouteReuseStrategy, useClass: AppRouteReuseStrategy },
         { provide: AppConfigService, useClass: DebugAppConfigService },
         {
             provide: TRANSLATION_PROVIDER,

src/app/app.routes.strategy.ts

@@ -0,0 +1,126 @@
+/*!
+ * @license
+ * Alfresco Example Content Application
+ *
+ * Copyright (C) 2005 - 2018 Alfresco Software Limited
+ *
+ * This file is part of the Alfresco Example Content Application.
+ * If the software was purchased under a paid Alfresco license, the terms of
+ * the paid license agreement will prevail.  Otherwise, the software is
+ * provided under the following open source license terms:
+ *
+ * The Alfresco Example Content Application is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * The Alfresco Example Content Application is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import {
+    RouteReuseStrategy,
+    DetachedRouteHandle,
+    ActivatedRouteSnapshot
+} from '@angular/router';
+
+interface RouteData {
+    reuse: boolean;
+}
+
+interface RouteInfo {
+    handle: DetachedRouteHandle;
+    data: RouteData;
+}
+
+export class AppRouteReuseStrategy implements RouteReuseStrategy {
+    private routeCache = new Map<string, RouteInfo>();
+
+    shouldReuseRoute(
+        future: ActivatedRouteSnapshot,
+        curr: ActivatedRouteSnapshot
+    ): boolean {
+        const ret = future.routeConfig === curr.routeConfig;
+        if (ret) {
+            this.addRedirectsRecursively(future); // update redirects
+        }
+        return ret;
+    }
+
+    shouldDetach(route: ActivatedRouteSnapshot): boolean {
+        const data = this.getRouteData(route);
+        return data && data.reuse;
+    }
+
+    store(route: ActivatedRouteSnapshot, handle: DetachedRouteHandle): void {
+        const url = this.getFullRouteUrl(route);
+        const data = this.getRouteData(route);
+        this.routeCache.set(url, { handle, data });
+        this.addRedirectsRecursively(route);
+    }
+
+    shouldAttach(route: ActivatedRouteSnapshot): boolean {
+        const url = this.getFullRouteUrl(route);
+        return this.routeCache.has(url);
+    }
+
+    retrieve(route: ActivatedRouteSnapshot): DetachedRouteHandle {
+        const url = this.getFullRouteUrl(route);
+        const data = this.getRouteData(route);
+        return data && data.reuse && this.routeCache.has(url)
+            ? this.routeCache.get(url).handle
+            : null;
+    }
+
+    private addRedirectsRecursively(route: ActivatedRouteSnapshot): void {
+        const config = route.routeConfig;
+        if (config) {
+            if (!config.loadChildren) {
+                const routeFirstChild = route.firstChild;
+                const routeFirstChildUrl = routeFirstChild
+                    ? this.getRouteUrlPaths(routeFirstChild).join('/')
+                    : '';
+                const childConfigs = config.children;
+                if (childConfigs) {
+                    const childConfigWithRedirect = childConfigs.find(
+                        c => c.path === '' && !!c.redirectTo
+                    );
+                    if (childConfigWithRedirect) {
+                        childConfigWithRedirect.redirectTo = routeFirstChildUrl;
+                    }
+                }
+            }
+            route.children.forEach(childRoute =>
+                this.addRedirectsRecursively(childRoute)
+            );
+        }
+    }
+
+    private getFullRouteUrl(route: ActivatedRouteSnapshot): string {
+        return this.getFullRouteUrlPaths(route)
+            .filter(Boolean)
+            .join('/');
+    }
+
+    private getFullRouteUrlPaths(route: ActivatedRouteSnapshot): string[] {
+        const paths = this.getRouteUrlPaths(route);
+        return route.parent
+            ? [...this.getFullRouteUrlPaths(route.parent), ...paths]
+            : paths;
+    }
+
+    private getRouteUrlPaths(route: ActivatedRouteSnapshot): string[] {
+        return route.url.map(urlSegment => urlSegment.path);
+    }
+
+    private getRouteData(route: ActivatedRouteSnapshot): RouteData {
+        return (
+            route.routeConfig && (route.routeConfig.data as RouteData)
+        );
+    }
+}

src/app/app.routes.ts

@@ -245,7 +245,8 @@ export const APP_ROUTES: Routes = [
                         path: '',
                         component: SearchResultsComponent,
                         data: {
-                            title: 'APP.BROWSE.SEARCH.TITLE'
+                            title: 'APP.BROWSE.SEARCH.TITLE',
+                            reuse: true
                         }
                     },
                     {