title: Typescript flatten an array of Map
body: <p>I have an array of <code>Map&lt;string, number&gt;</code></p>
  <p>How can I flat to a single map?</p>
  <pre><code>Map&lt;string, number&gt;[] to Map&lt;string, number&gt;
  </code></pre>
  <p>Thank you</p>