Continue to refactor service

dashboard/src/app/els.service.ts

@@ -171,20 +171,7 @@ export class ElsService {
               },
               'size': ElsService.DEFAULT_SIZE
             }), {headers: this.headers})
-      .map(res => this.responseToAlbum(res, albumName));
-  }
-
-  private responseToAlbum(res: Response, name: string): Album {
-    const hits = res.json().hits.hits;
-    if (hits.length < 1) {
-      console.info('No album "' + name + '" found.');
-      return undefined;
-    }
-    if (hits.length > 1) {
-      // TODO Cumul results
-      console.error('More than one album "' + name + '" found (' + hits.length + '), return the first.');
-    }
-    return hits[0]._source;
+      .map(res => this.responseToOneTypedResult<Album>(res, albumName));
   }
 
   getArtist(artistName: string): Observable<Artist> {
@@ -196,20 +183,7 @@ export class ElsService {
               },
               'size': ElsService.DEFAULT_SIZE
             }), {headers: this.headers})
-      .map(res => res.json().hits.hits)
-      .map((hits: Array<any>) => {
-        // Theorically, my script prevent to found two documents with this query.
-        // But Prevention is better than cure as Shakespeare said
-        if (hits.length < 1) {
-          console.info('No artist "' + artistName + '" found.');
-          return undefined;
-        }
-        if (hits.length > 1) {
-          console.error('More than one artist "' + artistName + '" found (' + hits.length + '), return the first.');
-          console.error('This is not normal!');
-        }
-        return hits[0]._source;
-      });
+      .map(res => this.responseToOneTypedResult<Artist>(res, artistName));
   }
 
   getGenres(ordering: string = 'desc'): Observable<Bucket[]> {
@@ -297,6 +271,31 @@ export class ElsService {
       });
   }
 
+  /** Process a result to return just one result.
+   * Used to get an album or an artist.
+   * Take a name to put in console output if no result or more than one result.
+   *
+   * @param res Response to process
+   * @param name The searched name - for console output
+   */
+  private responseToOneTypedResult<T>(res: Response, name: string): T {
+    const hits = res.json().hits.hits;
+
+    if (hits.length < 1) {
+      console.info('No result found for name: "' + name);
+      return undefined;
+    }
+    if (hits.length > 1) {
+      // TODO Cumul results (for album)
+      console.error('More than one result for name: "' + name + '". Found (' + hits.length + '), return the first.');
+    }
+    return hits[0]._source;
+  }
+
+  /** Process a response to a array of songs.
+   *
+   * @param res Response to process
+   */
   private responseToSongs(res: Response): Song[] {
     const result: Array<Song> = [];
     res.json().hits.hits.forEach((hit) => {