How should I access a variable after an async script is loaded?

Question

I have a setup tag for a Tracking service called Clicky that loads asynchronously on every page. I need to access "clicky" variable from another tag, which is only accessible after setup async script finishes loading.

For that reason, my tag script looks hacky. Is there any other way to check if an async script is loaded on Tag Manager context?

<script>  
  function clickyGoal() {
    try {
        clicky.goal('Email Capture');
    } catch(e) {
        setTimeout(clickyGoal, 200);
    }
  }
  clickyGoal();
</script>

EDIT: This is the main setup tag that fires on all pages.

<script type="text/javascript">
var clicky_site_ids = clicky_site_ids || [];
clicky_site_ids.push(<id-number>);
(function() {
  var s = document.createElement('script');
  s.type = 'text/javascript';
  s.async = true;
  s.src = '//static.getclicky.com/js';
  ( document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0] ).appendChild( s );
})();
</script>

Answer 1

You can use the onload property of the script tag to see when the script is loaded:

<script type="text/javascript">
var clicky_site_ids = clicky_site_ids || [];
clicky_site_ids.push(<id-number>);
(function() {
  var s = document.createElement('script');
  s.type = 'text/javascript';
  s.async = true;
  s.onload = function() {
      clicky.goal('Email Capture');
  };
  s.src = '//static.getclicky.com/js';
  ( document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0] ).appendChild( s );
})();
</script>

Answer 2

In your main set up tag, you should push an event once it has completed loading:

<script type="text/javascript">
var clicky_site_ids = clicky_site_ids || [];
clicky_site_ids.push(<id-number>);
(function() {
  var s = document.createElement('script');
  s.type = 'text/javascript';
  s.async = true;
  s.src = '//static.getclicky.com/js';
  ( document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0] ).appendChild( s );

  // push event to dataLayer
  dataLayer.push({
     'event': 'clicky ready'
  })
})();
</script>

In your subsequent tags that require the "clicky" variable, you would just need to add to your trigger the "clicky ready" event.