Angular 2 HttpClient Wrapper Problems

gistfile1.js

import {Injectable} from "@angular/core";
import {Http, RequestOptionsArgs, Response}  from "@angular/http";
import {UserInfo} from "./userInfo";
import {CatchSignature} from "rxjs/operator/catch";
import {Observable} from "rxjs";

/**
 * Wrapper around the Http provider to allow customizing HTTP requests
 */
@Injectable()
export class HttpClient {

  constructor(private http:Http, private user:UserInfo) {


  }

  get(url:string, requestOptions?:RequestOptionsArgs) {
    this.ensureOptions(!requestOptions);

    // want to return same behavior as Http provider
    // error: zone.js:344 Unhandled Promise rejection: this.http.get(...).catch is not a functio
    return this.http
      .get(url, requestOptions)
      .catch( response => {
         if (response.status == 401)
           this.user.isAuthenticated = false;
         return response; 
      });
  }
  ...
  
  ensureOptions(requestOptions:RequestOptionsArgs):RequestOptionsArgs {
    // this fails too
    // if (!requestOptions)
    //   requestOptions = <RequestOptionsArgs> {
    //     withCredentials: true
    //   };
    // else
    //   requestOptions.withCredentials = true;

    return requestOptions;
  }

}

// And this is how it's called
return this.http.get(this.config.urls.url("albums"))
      .toPromise()
      .then((response)=> {
        this.albumList = response.json();
        return this.albumList;
      });