title: How to use Bluebird in Typescript 2.1+
body: <p>(I have read <a href="https://stackoverflow.com/questions/39231151/how-to-use-bluebird-with-current-typescript">this post</a> but it is from August and it does not answer my question for the current typescript version.)</p>
  
  <p>I'm currently using Typescript 1.8 in my project and this works fine:</p>
  
  <pre><code>import * as Promise from "bluebird";
  async function f() : Promise&lt;void&gt; {
    return Promise.delay(200);
  }
  </code></pre>
  
  <p>But if I try to compile with Typescript 2.1:</p>
  
  <pre><code>index.ts(2,16): error TS1059: Return expression in async function does not have a valid callable 'then' member.
  </code></pre>
  
  <p>Googling the issue of using Bluebird Promises in Typscript, I have also found many github discussions, comments and PRs, but they are all very hard to grasp and while discussing interesting points, I can't find anywhere that says how I'm supposed to get this to work now.</p>
  
  <p>So, how am I supposed to be able to use Bluebird for Promises in Typescript 2.1?</p>