title: res.json() is a not a function in HttpClient Angular 2
body: <p>I was using Angular <code>Http</code> module before and the method <code>res.json()</code> used to work fine.
  I have recently tried <code>HttpClient</code> but then the <code>res.json()</code> dosen't seem to work . only using <code>res</code> works can some one tell me what changed has happened in the http client.</p>
  
  <pre><code>return this.client.get('https://swapi.co/api/people/1/')
                .map((res:Response) =&gt; {
                   return  res.json(); // using maps to filter data returned form the http call this json dosn't work with http client
                }).map(data =&gt; {
                  return data; // using maps of maps to filter data returned form the map
          }).flatMap((jedi) =&gt; this.http.get(jedi['homeworld'])
            .map(res =&gt; {
             return res.json().name; // using flat maps to combine data returned from two observables into one
            }).catch((error:any) =&gt; Observable.throw(error.json().error || 'Server error')));
  </code></pre>
  
  <p>I switched to http client because of the new interceptor can pointers are welcomed thanks</p>