code: function ToggleComponentService($mdComponentRegistry, $log, $q) {
      return function (contentHandle) {
        var errorMsg = "ToggleComponent '" + contentHandle + "' is not available!";
        var instance = $mdComponentRegistry.get(contentHandle);
  
        if (!instance) {
          $log.error('No content-switch found for handle ' + contentHandle);
        }
  
        return {
          isOpen: isOpen,
          toggle: toggle,
          open: open,
          close: close
        };
  
        function isOpen() {
          return instance && instance.isOpen();
        }
  
        function toggle() {
          return instance ? instance.toggle() : $q.reject(errorMsg);
        }
  
        function open() {
          return instance ? instance.open() : $q.reject(errorMsg);
        }
  
        function close() {
          return instance ? instance.close() : $q.reject(errorMsg);
        }
      };
    }
docs: ToggleComponent constructor
  AngularJS will instantiate a singleton by calling "new" on this function
  
  @ngdoc controller
  @name ToggleComponentService
  @module <%= scriptAppName %>.toggleComponent
  @returns {Object} The service definition for the ToggleComponent Service