Step debugging is not possible, too. The only thing you can do is to add log statements in your code, which isn’t a very productive debugging approach.
Fortunately, there is a switch to turn on the ability to debug your application.
When you load the Dojo library …
… simply add debugAtAllCosts: true to the djConfig attribute to make debugging work:
debugAtAllCosts will significantly slow down your application, so it is important to disable it when you deploy your application to a production environment.