In addition to the app properties and the app methods, as well the controls properties and methods, and, the integrated Apache Cordova plugins properties and methods, you can also add your own app functions. The existing app user functions are also integrated in the IDE Quick code list.
The app user functions can be a good way, for example, to share some pieces of code along the app, since you can call to that app user functions from any app view, app dialog, etc. The DecSoft App Builder IDE provides you an app user functions manager, and, you can define any number of app user functions.
Take a look at the below animated GIF image, in which you can see how to create a new app user function and then use it.
The user functions that you add to the app are placed in the "app" scoped, as any other method of the app, so, if you add a "sayHello" user function, you can call to that function with the below code: