Can Angular have an "event" that fires when the scope variables change?

Question

JavaScript

Can Angular have an "event" that fires when the scope variables change?
This is what should be the result, the user does some actions in the application and if he changes some indicator, what would it be sent to the server.
I fully understand that you can make a super setinterval that will compare each variable, but in my opinion this bike is still the same, but I want to increase the quality.

Answer 1

$watch
https://docs.angularjs.org/api/ng/type/$rootScope.Scope

Answer 2

For angular 1.5 there is $onChanges ( for components).
For inputs - ng-model + ng-change is enough