title: Does Google Tag Manager support ES6 now?
body: <p>I want use Custom Javascript in variables.<br />
  I know GTM didn't support ES6 before.<br />
  I read this post:<br />
  <a href="https://stackoverflow.com/a/64704436/18767822">https://stackoverflow.com/a/64704436/18767822</a></p>
  <p>Does GTM support ES6 now? or yet?<br />
  thanks!</p>