Scope events propagation

Types

• Broadcasted
• Emitted

Broadcasted

$scope.$broadcast('MyEvent',args...)


$scope.$on('MyEvent', function(event,args...) {
    //do something
  });

Events to the scope children

Emitted 

$scope.$emit('MyEvent',args...)


 $scope.$on('MyEvent', function(event,args...) {
    //do something
  });

Events to the scope parents

$scope.watch

$scope.watch depths

• by reference
• collection contents
• by value

By reference

Detects a change when the whole value returned by the watch expression switches to a new value. If the value is an array or an object, changes inside it are not detected. This is the most efficient strategy.

scope.name = 'misko';

scope.$watch('name', function(newValue, oldValue) {
  scope.counter = scope.counter + 1;
});

Watch collection

Detects changes that occur inside an array or an object: When items are added, removed, or reordered. The detection is shallow - it does not reach into nested collections. Watching collection contents is more expensive than watching by reference
    

$scope.names = ['igor', 'matias', 'misko', 'james'];

$scope.$watchCollection('names', function(newNames, oldNames) {
 
});

By value

Detects any change in an arbitrarily nested data structure. It is the most powerful change detection strategy, but also the most expensive.
    

scope.name = 'misko';

scope.$watch('name', function(newValue, oldValue) {
  scope.counter = scope.counter + 1;
}, true);