Most played song - good way to retrieve data

dashboard/src/app/els.service.ts

@@ -30,27 +30,32 @@ export class ElsService {
                     .catch(this.handleError);
   }
 
-  getTrackCountO(type: string): Observable<number> {
-    return this.http.get(this.elsUrl + type + "/_count")
-                    .map(res => res.json().count as number);
-  }
+  getMostPlayedTrack(): Observable<Song[]> {
+    // Thank to http://chariotsolutions.com/blog/post/angular2-observables-http-separating-services-components/
 
-  getMostPlayedTrack(): Promise<Hits[]> {
-    return this.http.post(this.elsUrl + "song/_search",
-                      JSON.stringify({"sort":[{"Play Count":{"order":"desc"}}],"size": 5}),
-                      {headers: this.headers})
-                    .toPromise()
-                    .then(res => res.json().hits.hits)
-                    .catch(this.handleError);
-  }
-
-  getMostPlayedTrackO(): Observable<Object[]> {
+    // Could be shorter but I think it's more readable like this.
     return this.http
-               .post(this.elsUrl + "song/_search",
-                  JSON.stringify({"sort":[{"Play Count":{"order":"desc"}}],"size": 5}),
-                  {headers: this.headers})
-               .map(response => response.json().hits.hits as Object[]);
-               // TODO Treat data here to return song instead of in subscribe
+      .post(this.elsUrl + "song/_search",
+            JSON.stringify({"sort":[{"Play Count":{"order":"desc"}}],"size": 5}),
+            {headers: this.headers})
+      .map(res => {
+        return res.json().hits.hits;
+      })
+      .map((hits: Array<any>) => {
+        let result:Array<Song> = [];
+        hits.forEach((hit) => {
+          result.push(hit._source);
+        });
+        return result;
+      });
+      // Shorter way:
+      // .map(res => {
+      //   let result: Array<Song> = [];
+      //   res.json().hits.hits.forEach(element => {
+      //     result.push(element._source);
+      //   });
+      //   return result;
+      // });
   }
 
   private handleError(error: any): Promise<any> {