app/common/directives/loader.js

window.angular && (function(angular) {
  'use strict';

  angular
    .module('app.common.directives')
    .directive('loader', function() {
      return {
        'restrict': 'E',
        'template': require('./loader.html'),
        scope: {
          loading: '='
        }
      };
    });

})(window.angular);