app.js

var oldModelValue, newModelValue, counter;


function watchModelFn(scope) {
  newModelValue = ngModelGet(scope);
  if (
    !updatingFromTheView &&
    !(newModelValue === undefined && $valid === false) &&
    !modelEquals(newModelValue, oldModelValue)
  ) {
    counter++;
    oldModelValue = modelCopy(newModelValue);
  }
  updatingFromTheView = false;
  return counter;
}


function watchHandler() {
  
  ctrl.$modelValue = newModelValue;

  var newViewValue = runFormatters(ctrl.$modelValue);

  if (!viewEquals(newViewValue, viewCopy(ctrl.$viewValue))) {
    ctrl.$viewValue = newViewValue;
    render();
    runValidators($viewValue);
  }
}


// Simple things
simpleEquals = function(lhs, rhs) { return lhs === rhs; };
simpleCopy = function(val) { return val; };

// Objects
objectEquals = angular.equals
objectCopy = angular.copy

// More complex