Page 174 ds.add() causes Uncaught Type Error

Typing at the Console in Chrome:

typed> var ds = new App.DataStore();
datastore.js:15 running DataStore function
typed>ds.add(‘email’, ‘’);
VM209:1 Uncaught TypeError: ds.add is not a function
at :1:4

Assume the code from page 174 is entered correctly (things worked as described to this point) –
so not sure how to fix this?

Here is the code added as described by page 174:

DataStore.prototype.add = function (key, val) { // page 174[key] = val;

Thanks for suggestions/fixes in advance, marz

This error was fixed by refreshing the browser. In other words, operator error. :o