Handlebars RegisterHelper with Ember Error

I'm pretty lost after trying numerous different things. I am building an Ember site and inside of one of my Handlebars templates, I want to display a link only if a condition is true. Here is my template.

<script type="text/x-handlebars" data-template-name="project">
    <div class="project-container">
        {{is_external model.url model.title}}
    </div>
</script>

Now, my registerHelper in my js file:

Handlebars.registerHelper('is_external', function(url, title, options) {
  if (url.indexOf("codepen") < 0) {
      return "<p class='view-external-link'>"+
            "<a href='{{url}}'' aria-label='View {{title}}'' target='_blank'>Visit Site</a>"+
            "</p>";
  }
});

The error I keep receiving however, is: Uncaught TypeError: Cannot read property 'isHelperFactory' of undefined coming from my ember.js file.

Ideally, I would prefer to just return true or false from the helper to keep the Html out of my helper function but first I just need some help getting it working.

I am including ember, ember_compiler, and handlebars on my page as well.