transform(items: Observable<any>, typeFilter: any): any {
        if (items == null) {
            return [];
        }

        if (typeFilter) {
            return items.filter(i => i.type === typeFilter);
        }

        return items;
    }

 public deleteNoteById(keepId: number): Observable<null> {
   const index = this.keeps.findIndex(x => x.id === keepId);
   this.keeps.slice(index, 1);
   return Observable.of(null);
 }

 public getNoteById(keepId: number): Observable<KeepModel> {
   return Observable.of(this.keeps.find(x => x.id === keepId));
 }

 public getAllNotes(): Observable<KeepModel[]> {
   return Observable.of(this.keeps);
 }