Implementing infinite scroll for library items

package.json

@@ -9,37 +9,38 @@
   },
   "private": true,
   "dependencies": {
-    "@angular/animations": "^9.1.9",
+    "@angular/animations": "^9.1.12",
     "@angular/cdk": "^9.2.4",
-    "@angular/common": "^9.1.9",
+    "@angular/common": "^9.1.12",
-    "@angular/compiler": "^9.1.9",
+    "@angular/compiler": "^9.1.12",
-    "@angular/core": "^9.1.9",
+    "@angular/core": "^9.1.12",
-    "@angular/forms": "^9.1.9",
+    "@angular/forms": "^9.1.12",
     "@angular/material": "^9.2.4",
-    "@angular/platform-browser": "^9.1.9",
+    "@angular/platform-browser": "^9.1.12",
-    "@angular/platform-browser-dynamic": "^9.1.9",
+    "@angular/platform-browser-dynamic": "^9.1.12",
-    "@angular/router": "^9.1.9",
+    "@angular/router": "^9.1.12",
     "angular-auth-oidc-client": "10.0.14",
     "bootstrap": "^4.5.0",
-    "detect-browser": "^5.1.0",
+    "detect-browser": "^5.1.1",
     "hammerjs": "^2.0.8",
     "hls.js": "^0.13.2",
     "jquery": "^3.5.1",
+    "ngx-infinite-scroll": "^9.0.0",
     "popper.js": "^1.16.1",
     "zone.js": "^0.10.3"
   },
   "devDependencies": {
-    "@angular-devkit/build-angular": "^0.901.7",
+    "@angular-devkit/build-angular": "^0.901.12",
-    "@angular/cli": "^9.1.7",
+    "@angular/cli": "^9.1.12",
-    "@angular/compiler-cli": "^9.1.9",
+    "@angular/compiler-cli": "^9.1.12",
-    "@angular/language-service": "^9.1.9",
+    "@angular/language-service": "^9.1.12",
     "@types/bootstrap": "^4.5.0",
     "@types/hls.js": "^0.12.6",
-    "@types/jasmine": "^3.5.10",
+    "@types/jasmine": "^3.5.11",
     "@types/jasminewd2": "^2.0.8",
-    "@types/jquery": "^3.3.38",
+    "@types/jquery": "^3.5.1",
-    "@types/node": "^13.13.10",
+    "@types/node": "^13.13.15",
-    "@types/video.js": "^7.3.9",
+    "@types/video.js": "^7.3.10",
     "codelyzer": "^5.2.2",
     "protractor": "^7.0.0",
     "ts-node": "~8.6.2",

src/app/app-routing.module.ts

@@ -14,7 +14,7 @@ import {StreamResolverService} from "./services/resolvers/stream-resolver.servic
 import {ShowDetailsComponent} from './pages/show-details/show-details.component';
 import {AuthGuard} from "./auth/misc/authenticated-guard.service";
 import {LibraryItem} from "../models/library-item";
-import {CrudApi, LibraryItemService, LibraryService} from "./services/api.service";
+import {LibraryItemService, LibraryService} from "./services/api.service";
 
 const routes: Routes = [
 	{path: "browse", component: LibraryItemGridComponent, pathMatch: "full",

src/app/app.module.ts

@@ -40,6 +40,7 @@ import {MatChipsModule} from "@angular/material/chips";
 import {MatAutocompleteModule} from "@angular/material/autocomplete";
 import {MatExpansionModule} from "@angular/material/expansion";
 import {ShowGridComponent} from './components/show-grid/show-grid.component';
+import {InfiniteScrollModule} from "ngx-infinite-scroll";
 
 
 @NgModule({
@@ -87,7 +88,8 @@ import { ShowGridComponent } from './components/show-grid/show-grid.component';
 		AuthModule,
 		MatChipsModule,
 		MatAutocompleteModule,
-		MatExpansionModule
+		MatExpansionModule,
+		InfiniteScrollModule
 	],
 	bootstrap: [AppComponent]
 })

src/app/components/library-item-grid/library-item-grid.component.html

@@ -24,7 +24,7 @@
 	</div>
 </mat-menu>
 
-<div class="container-fluid justify-content-center">
+<div class="container-fluid justify-content-center" infinite-scroll (scrolled)="this.page?.loadNext(this.client)">
 	<a class="show" *ngFor="let item of this.page.items" [href]="getLink(item)" [routerLink]="getLink(item)">
 		<div matRipple [style.background-image]="getThumb(item.slug)" > </div>
 		<p class="title">{{item.title}}</p>

src/app/components/library-item-grid/library-item-grid.component.ts

@@ -4,6 +4,7 @@ import {DomSanitizer} from '@angular/platform-browser';
 import {ItemType, LibraryItem} from "../../../models/library-item";
 import {Page} from "../../../models/page";
 import {LibraryItemService} from "../../services/api.service";
+import {HttpClient} from "@angular/common/http";
 
 @Component({
 	selector: 'app-browse',
@@ -18,7 +19,10 @@ export class LibraryItemGridComponent
 	sortKeys: string[] = ["title", "start year", "end year", "status", "type"]
 	sortUp: boolean = true;
 
-	constructor(private route: ActivatedRoute, private sanitizer: DomSanitizer, private items: LibraryItemService)
+	constructor(private route: ActivatedRoute,
+	            private sanitizer: DomSanitizer,
+	            private items: LibraryItemService,
+	            public client: HttpClient)
 	{
 		this.route.data.subscribe((data) =>
 		{

src/app/services/api.service.ts

@@ -1,11 +1,11 @@
 import {Injectable} from "@angular/core";
 import {HttpClient} from "@angular/common/http";
 import {Observable} from "rxjs"
-import {map} from "rxjs/operators"
 import {Page} from "../../models/page";
 import {IResource} from "../../models/resources/resource";
 import {Library} from "../../models/library";
 import {LibraryItem} from "../../models/library-item";
+import {map} from "rxjs/operators";
 
 class CrudApi<T extends IResource>
 {
@@ -23,19 +23,8 @@ class CrudApi<T extends IResource>
 			params += "sortBy=" + args.sort;
 		if (params == "?")
 			params = "";
-		return this.client.get<Page<T>>(`/api/${this.route}${params}`);
+		return this.client.get<Page<T>>(`/api/${this.route}${params}`)
-	}
+			.pipe(map(x => Object.assign(new Page<T>(), x)));
-
-	loadNext(page: Page<T>): Observable<Page<T>>
-    {
-	    if (page.next == null)
-	    	return;
-		return this.client.get<Page<T>>(page.next).pipe(map(x =>
-		{
-			x.items = page.items.concat(x.items);
-			x.count += page.count;
-			return x;
-		}));
 	}
 
 	create(item: T): Observable<T>

src/app/services/resolvers/library-resolver.service.ts

@@ -3,7 +3,7 @@ import { Injectable } from '@angular/core';
 import { MatSnackBar } from '@angular/material/snack-bar';
 import { ActivatedRouteSnapshot, Resolve } from '@angular/router';
 import { EMPTY, Observable } from 'rxjs';
-import { catchError } from 'rxjs/operators';
+import {catchError, map} from 'rxjs/operators';
 import {Page} from "../../../models/page";
 import {IResource} from "../../../models/resources/resource";
 
@@ -15,20 +15,23 @@ export class PageResolver
 	static forResource<T extends IResource>(resource: string)
 	{
 		@Injectable()
-		class Resolver<T> implements Resolve<Page<T>>
+		class Resolver implements Resolve<Page<T>>
 		{
 			constructor(private http: HttpClient, private snackBar: MatSnackBar) { }
 
 			resolve(route: ActivatedRouteSnapshot): Page<T> | Observable<Page<T>> | Promise<Page<T>>
 			{
-				return this.http.get<Page<T>>(`api/${resource}`).pipe(catchError((error: HttpErrorResponse) =>
+				return this.http.get<Page<T>>(`api/${resource}`)
+					.pipe(
+						map(x => Object.assign(new Page<T>(), x)),
+						catchError((error: HttpErrorResponse) =>
 						{
 							console.log(error.status + " - " + error.message);
 							this.snackBar.open(`An unknown error occurred: ${error.message}.`, null, {
 								horizontalPosition: "left",
 								panelClass: ['snackError'],
-						duration: 2500 }
+								duration: 2500
-					);
+							});
 							return EMPTY;
 						}));
 			}

src/models/page.ts

@@ -1,8 +1,26 @@
-export interface Page<T>
+import {HttpClient} from "@angular/common/http";
+
+export class Page<T>
 {
 	this: string
 	next: string
 	first: string
 	count: number
 	items: T[]
+
+	constructor() {}
+
+	loadNext(client: HttpClient)
+	{
+		if (this.next == null)
+			return;
+
+		client.get<Page<T>>(this.next).subscribe(x =>
+		{
+			this.items.push(...x.items);
+			this.count += x.count;
+			this.next = x.next;
+			this.this = x.this;
+		});
+	}
 }