title: Can not load RxJs
body: <p>I use this import statement in one of component file:</p>
  
  <pre><code>import {BehaviorSubject} from 'rxjs';
  @Injectable()
  export class UserService {
      private currentUser = new BehaviorSubject&lt;User&gt;(null);
  }
  </code></pre>
  
  <p>When the browser loads the app, it throws the exception below:</p>
  
  <pre><code>SyntaxError: Unexpected token &lt;
  Evaluating http://localhost:3000/rxjs
  Error loading http://localhost:3000/app/components/app.js
  at eval (native)
  at SystemJSLoader.__exec (http://localhost:3000/vendors.js:3320:16)
  </code></pre>
  
  <p>I don't know why it didn't work. Cause Angular2 worked already.
  Could any one please help me this case?</p>