$watch ngModel from inside directive using isolate scope

You’ll need to watch a function that returns the $modelValue you’re watching.

The following code shows a basic example:

app.directive('myDirective', function (){
    return {
        require: 'ngModel',
        link: function(scope, element, attrs, ngModel) {
           scope.$watch(function () {
              return ngModel.$modelValue;
           }, function(newValue) {
               console.log(newValue);
           });
        }
     };
});

Here’s a plunker of the same idea in action.