Angular $scope.$watch on (for in... ) don't work

Angular $scope.$watch on (for in... ) don't work



in my code i have the following for watch changes in some variables

$scope.$watch('ns.namespace.watchable_value', function(newVal, oldVal){

//...

})

now i have many namespaces with a watchable_value and I wanna do

for (namespace in [...]) {

$scope.$watch('ns.' + namespace + '.watchable_value', function(newVal,

oldVal){

//...

})

}

but the callback never is called