title: this.http.post(...).map is not a function
body: <pre><code>doSelectMessagesAttributesUrl1(pushRequest : PushRequest) {
      console.info("sending post request");
  
      let headers = new Headers({
          'Content-Type': 'application/x-www-form-urlencoded'});
  
      return this.http
          .post(this.selectMessagesAttributesUrl, {headers: headers})
          .map(res =&gt; res.json().data)
          .subscribe(
              data =&gt; { },
              err =&gt; { console.error('An error occurred', err) }
          );
  }
  </code></pre>
  
  <p>I get this error:</p>
  
  <pre><code>EXCEPTION: TypeError: this.http.post(...).map is not a functionBrowserDomAdapter.logError @ platform-browser.umd.js:937
  zone.js:461 
  
  Unhandled Promise rejection: this.http.post(...).map is not a function ; Zone: &lt;root&gt; ; Task: Promise.then ; Value: TypeError: this.http.post(...).map is not a function(…)
  </code></pre>
  
  <p>what is missing in my http syntax?</p>