Best way to import Observable from rxjs : <p>In my angular 2 app I have a service that uses the <code>Observable</code> class from the <code>rxjs</code> library.</p>

<pre><code>import { Observable } from 'rxjs';
</code></pre>

<p>At the moment I am just using <code>Observable</code> so that I can use the <code>toPromise()</code> function.</p>

<p>I read in another StackOverflow question somewhere that importing in this way and also importing from <code>rxjs/Rx</code> will import a whole lot of unnecessary stuff from the <code>rxjs</code> library that will increase the page load times and/or the code base.</p>

<p>My question is, what is the best way to import <code>Observable</code> so I can use the <code>toPromise()</code> function without having to import everything else?</p>
