product-panels.js

app.directive('productPanels', function(){
  return {
      restrict: 'E',
      templateUrl: 'product-panels.html',
      controller: function () {
          this.tab = 'description';

          this.setTab = function (tab) {
              this.tab = tab;
          };

          this.isSelected = function (tab) {
              return this.tab === tab;
          }
      },
      controllerAs: 'panel'
  };
});