gistfile1.txt

@Injectable()
export class CommentService {
     // Resolve HTTP using the constructor
     constructor (private http: Http) {}
     // private instance variable to hold base url
     private commentsUrl = 'http://localhost:3000/api/comments'; 
}
  getComments() : Observable<Comment[]> {
    // ...using get request
    return this.http.get(this.commentsUrl)
    // ...and calling .json() on the response to return data
    .map((res:Response) => res.json())
     //...errors if any
    .catch((error:any) => Observable.throw(error.json().error || 'Server error'));

}