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Angular's $watch function allows events to be fired when the specified attribute changes, as shown below. Is there is a similar way to listen for events when any change happens on the scope?
// works
$scope.$watch("someval", function() { }, true);
$scope.$watch(function(scope){ return scope.someval; }, function() { }, true);
// doesn't work
$scope.$watch("this", function() { }, true);
$scope.$watch(function(scope){ return scope; }, function() { }, true);
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A watch means that AngularJS watches changes in the variable on the $scope object. The framework is "watching" the variable. Watches are created using the $scope. $watch() function which I will cover later in this text. At key points in your application AngularJS calls the $scope.
$apply() function will execute custom code and then it will call $scope. $digest() function forcefully to check all watch list variables and update variable values in view if any changes found for watch list variables. In most of the time angularjs will use $scope.
The angular JS $watch function is used to watch the scope object. The $watch keep an eye on the variable and as the value of the variable changes the angular JS $what runs a function. This function takes two arguments one is the new value and another parameter is the old value.
Scope InheritanceIf we define nested controllers, then the child controller inherits the scope of its parent controller. We assign values to the models in shapeController. We override message in child controller named circleController.
I believe you cannot watch for changes on the $scope (apart from using @ValentynShybanov's sugestion). The closest thing you can do is to watch for digest calls:
$scope.$watch(function() {
console.log("digest called");
});
The above function will be called each time a $digest is invoked on the scope, even if there were no changes on the scope's properties.
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