Enable scrollPositionRestoration in router. Code cleanup

With the new scrollPositionRestoration option of Angular 6.1 we can
simplify the code controlling the scroll.

Going back to the AppListComponent doesn't work very well, as
scrollPositionRestoration has issues when data is loaded dynamically

More info about this at angular/angular#24547

src/app/app-routing.module.ts

@@ -67,7 +67,7 @@ const appRoutes: Routes = [
       appRoutes,
       {
         enableTracing: false, // <-- debugging purposes only
-        scrollPositionRestoration: 'top',
+        scrollPositionRestoration: 'enabled',
         //anchorScrolling: 'enabled',
         scrollOffset: [0, 0] // [x, y]
       }

src/app/pages/about/about.component.ts

@@ -1,5 +1,4 @@
 import { Component, OnInit } from '@angular/core';
-import { NavigationEnd, Router } from '@angular/router';
 import { SeoService } from '../../seo.service';
 
 @Component({
@@ -9,22 +8,11 @@ import { SeoService } from '../../seo.service';
 })
 export class AboutComponent implements OnInit {
 
-  constructor(
-    private router: Router,
-    private seoService: SeoService) {
-
+  constructor(private seoService: SeoService) {
     this.setPageMetadata();
-
   }
 
-  ngOnInit() {
-    this.router.events.subscribe((evt) => {
-      if (!(evt instanceof NavigationEnd)) {
-        return;
-      }
-      window.scrollTo(0, 0);
-    });
-  }
+  ngOnInit() { }
 
   setPageMetadata() {
 

src/app/pages/app-details/app-details.component.ts

@@ -1,9 +1,12 @@
 import { Component, OnInit, Input } from '@angular/core';
-import { Router, NavigationEnd } from '@angular/router';
-import { ActivatedRoute, ParamMap } from '@angular/router';
+import { ViewportScroller } from '@angular/common';
+import { Router } from '@angular/router';
+import { ActivatedRoute } from '@angular/router';
+
 import { Location } from '@angular/common';
 import { SeoService } from '../../seo.service';
 
+
 import { App } from '../../shared/app.model';
 import { Review } from '../../shared/review.model';
 import { LinuxStoreApiService } from '../../linux-store-api.service';
@@ -18,6 +21,7 @@ export class AppDetailsComponent implements OnInit {
 
   @Input() app: App;
 
+  scrollPosition: [number, number];
   paramAppId: string;
 
   reviews: Review[];
@@ -30,11 +34,12 @@ export class AppDetailsComponent implements OnInit {
     private googleAnalyticsEventsService: GoogleAnalyticsEventsService,
     private router: Router,
     private route: ActivatedRoute,
+    private viewportScroller: ViewportScroller,
     private location: Location,
     private seoService: SeoService) {
+  }
 
 
-  }
 
   setPageMetadata() {
 
@@ -86,13 +91,6 @@ export class AppDetailsComponent implements OnInit {
         this.getApp(this.paramAppId);
       }
     );
-
-    this.router.events.subscribe((evt) => {
-      if (!(evt instanceof NavigationEnd)) {
-        return;
-      }
-      window.scrollTo(0, 0);
-    });
   }
 
   getApp(id: string): void {

src/app/pages/app-list/app-list.component.ts

@@ -1,7 +1,7 @@
 import { Component, OnInit } from '@angular/core';
-import { ElementRef, ViewChild } from '@angular/core';
-import { Router, ActivatedRoute, ParamMap, NavigationEnd } from '@angular/router';
-import { BreakpointObserver, Breakpoints } from '@angular/cdk/layout';
+import { ViewChild } from '@angular/core';
+import { Router, ActivatedRoute } from '@angular/router';
+import { BreakpointObserver } from '@angular/cdk/layout';
 import { SeoService } from '../../seo.service';
 
 import { App } from '../../shared/app.model';
@@ -18,6 +18,8 @@ export class AppListComponent implements OnInit {
 
   @ViewChild('drawer') drawer;
 
+  scrollPosition: [number, number];
+
   apps: App[];
   categories: Category[];
   selectedCategory: Category;
@@ -39,6 +41,7 @@ export class AppListComponent implements OnInit {
   }
 
   ngOnInit() {
+
     this.getCategories();
     this.getFeaturedCollections();
 
@@ -52,13 +55,6 @@ export class AppListComponent implements OnInit {
         }
       }
     );
-
-    this.router.events.subscribe((evt) => {
-      if (!(evt instanceof NavigationEnd)) {
-        return;
-      }
-      window.scrollTo(0, 0);
-    });
   }
 
   isSmallScreen(): boolean {
@@ -118,6 +114,7 @@ export class AppListComponent implements OnInit {
         'Developer Tools, Education, Games, Graphics & Photography, Communication & News, Productivity, Science, Settings, Utilities, ...',
         this.getFlathubMetaImage());
     }
+
   }
 
   showAppsSearchKeyword(searchKeyword: string): void {

src/app/pages/home/home.component.ts

@@ -1,5 +1,5 @@
 import { Component, OnInit } from '@angular/core';
-import { Router, NavigationEnd } from '@angular/router';
+import { Router } from '@angular/router';
 
 import { App } from '../../shared/app.model';
 import { Collection } from '../../shared/collection.model';
@@ -28,13 +28,6 @@ export class HomeComponent implements OnInit {
   }
 
   ngOnInit() {
-    this.router.events.subscribe((evt) => {
-      if (!(evt instanceof NavigationEnd)) {
-        return;
-      }
-      window.scrollTo(0, 0);
-    });
-
     this.linuxStoreApiService.getFeaturedCollections()
       .subscribe(collections => {
         this.featuredCollections = collections;