Looks like AngularJS added “getter” “setter” support in version 1.3
You can scroll to the bottom of their ngModel documentation page at:
https://docs.angularjs.org/api/ng/directive/ngModel
This allows you to specify a method instead of a variable in your ngModel attribute. The method should take an optional parameter. If an argument is passed it should store that value, if no argument is passed it should return a value.
You can see an example in another Stack Overflow answer at: https://stackoverflow.com/a/28224980/984780