RESTService transform function at a method level

[emoralesb05]

Feature Request

A way to override the transformation (transform) function provided at a service level.

What is the expected behavior?

Be able to return a parsed or diff object without affecting the other methods from any RESTService methods (query, get, etc etc).

e.g. Wanting to parse the response before returning it or returning response headers with the data.

Usage

Current:

public query(query?: IRestQuery): Observable<Array<T>> {
    let request: Observable<Response> = this.http.get(this.buildUrl(undefined, query), this.buildRequestOptions());
    return request.map<Array<T>>((res: Response) => {
      return <Array<T>>this.transform(res);
    }).catch<any>((error: Response) => {
      return new Observable<any>((subscriber: Subscriber<any>) => {
        try {
          subscriber.error(this.transform(error));
        } catch (err) {
          subscriber.error(error);
        }
      });
    });
  }

Desired (maybe):

public query(query?: IRestQuery, transform?: IRestTransform): Observable<Array<T>> {
    let request: Observable<Response> = this.http.get(this.buildUrl(undefined, query), this.buildRequestOptions());
    return request.map<Array<T>>((res: Response) => {
      if (transform) {
         return <any>transform(res);
      }
      return <Array<T>>this.transform(res);
    }).catch<any>((error: Response) => {
      return new Observable<any>((subscriber: Subscriber<any>) => {
        try {
          subscriber.error(this.transform(error));
        } catch (err) {
          subscriber.error(error);
        }
      });
    });
  }

[emoralesb05]

Added with #192