text: (function() {
      angular.module("todoApp")
          .service("ToDoService", function() {
              var self = this;
              self.isValidItem = function(itemName, callBack) {
                  if (itemName) {
                      callBack(itemName);
                      return true;
                  } else {
                      return false;
                  }
              };
          });
  
  
  })();
  