title: Optional catch in javascript promises
body: <p>The following is valid:</p>
  
  <pre><code>new Promise&lt;void&gt;((resolve, reject) =&gt; {
        reject()
      })
      .then(() =&gt; {})
      .catch(() =&gt; {})
  </code></pre>
  
  <p>But I might not always care about the error. Is there a way to make the catch optional?</p>
  
  <p>I tried this but it didn't work:</p>
  
  <pre><code>new Promise&lt;void&gt;((resolve, reject?) =&gt; {
        if (reject) reject()
      })
      .then(() =&gt; {})
  </code></pre>
  
  <p><code>Error: Uncaught (in promise): undefined</code></p>