How do I use $scope.$watch and $scope.$apply in AngularJS?

Question

I don\'t understand how to use $scope.$watch and $scope.$apply. The official documentation isn\'t helpful.

What I don\'t understand specifi

Answer 1

There are $watchGroup and $watchCollection as well. Specifically, $watchGroup is really helpful if you want to call a function to update an object which has multiple properties in a view that is not dom object, for e.g. another view in canvas, WebGL or server request.

Here, the documentation link.