index.js

/* jshint node: true */
'use strict';

module.exports = {
  name: 'ember-cli-gtm',

  contentFor: function(type, config) {
    var config = config['ember-cli-gtm'];
    var appId = config && config.appId;
    if (type === 'head' && appId) {
      return "<!-- Google Tag Manager --><script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','"+ appId +"');</script><!-- End Google Tag Manager -->";
    }

    if (type === 'body' && appId) {
      return '<!-- Google Tag Manager (noscript) --><noscript><iframe src="https://www.googletagmanager.com/ns.html?id=' + appId + '"height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript><!-- End Google Tag Manager (noscript) -->';
    }
  }
};