saving with admin and public base

src/app/admin/banner/banner.service.ts

@@ -0,0 +1,66 @@
+import { Injectable } from '@angular/core';
+import { HttpClient } from '@angular/common/http';
+import { Observable } from 'rxjs';
+import { delay, map } from 'rxjs/operators';
+import { Apollo } from 'apollo-angular';
+import { FIND_UNIQUE_BANNER, LIST_BANNERS } from './graphql/queries';
+import { Banner } from './banner.model';
+import { CREATE_BANNER, UPDATE_BANNER } from './graphql/mutations';
+
+const TOTAL_PAGES = 7;
+
+export class NewsPost {
+  title: string;
+  link: string;
+  creator: string;
+  text: string;
+}
+
+@Injectable()
+export class BannerService {
+
+  constructor(private http: HttpClient, private readonly apollo: Apollo) {}
+
+  load(page: number, pageSize: number): Observable<NewsPost[]> {
+    const startIndex = ((page - 1) % TOTAL_PAGES) * pageSize;
+
+    return this.http
+      .get<NewsPost[]>('assets/data/news.json')
+      .pipe(
+        map(news => news.splice(startIndex, pageSize)),
+        delay(1500),
+      );
+  }
+
+  listBanners(): Observable<any> {
+    return this.apollo
+      .watchQuery<Banner>({
+        query: LIST_BANNERS(),
+      })
+      .valueChanges
+  }
+
+  findUniqueBanner(id: Banner["id"]): Observable<any> {
+    return this.apollo
+      .watchQuery<Banner>({
+        query: FIND_UNIQUE_BANNER(id),
+      })
+      .valueChanges
+  }
+
+  createBanner(banner: Banner) {
+    console.log(CREATE_BANNER(banner));
+    return this.apollo
+      .mutate<any>({
+        mutation: CREATE_BANNER(banner),
+      });
+  }
+
+  updateBanner(banner: Banner) {
+    console.log(UPDATE_BANNER(banner));
+    return this.apollo
+      .mutate({
+        mutation: UPDATE_BANNER(banner),
+      });
+  }
+}