title: Typescript Error: setInterval - Type 'Timer' is not assignable to type 'number'
body: <p>I have the following code:</p>
  
  <pre><code>let onSizeChangeSetInterval = setInterval(() =&gt; {...}, 30);
  </code></pre>
  
  <p>When I compile this code, I'm getting the following error:</p>
  
  <blockquote>
    <p>ERROR in src/components/popover/popover.component.ts(98,17): error TS2322: Type 'Timer' is not assignable to type 'number'.
    src/modules/forms-ui/formly/types/daterange/picker.daterange.component.ts(186,9): error TS2322: Type 'Timer' is not assignable to type 'number'.</p>
  </blockquote>