javascript - variable change not notified to `$scope.$watch` -

i handling jqrangeslider through angular directive + controller.

within controller, assigning new values scope variables there change not notified controller scope (i using isolated scope '=' in directive) though correctly updated.

// jqrangeslider event handler var valueschanged = function(e, data) {     if (data.values.min && data.values.max) {          console.log('values changed', data.values); // printed         $scope.minselectedtime = data.values.min; // not triggering $scope.$watch         $scope.maxselectedtime = data.values.max;          $scope.$broadcast('minchanged', $scope.minselectedtime); // instantly triggering $scope.$on('minchanged',...)         console.log('scope', $scope);     } };   $scope.$watch('minselectedtime', function(newvalue, oldvalue) {     if (newvalue === oldvalue) {         return;     }     console.log('minselectedtime -->', newvalue); }, true);  $scope.$on('minchanged', function(event, min) {     console.log('minchanged ==>', min); }); 

$scope.$watch('minselectedtime', ...) triggered on next $scope modification (where $scope.minselectedtime not modified):

$scope.toggletimescale = function(refinementstring) {     console.log('scale set to', refinementstring);     $scope.timescale = refinementstring; // year, month, day... }  

why isn't $scope.$watch immediatly notified of variable change?
isolated code has $scope.minselectedtime value changed parent scope doesn't see value changed until $scope.toggletimescale triggered.

your method of using $scope.$apply() correct. reason being update jqrangeslider happened 'outside' of angularjs knowledge. if read documentation on $apply method (http://docs.angularjs.org/api/ng.$rootscope.scope#$apply) you'll see it's used in case need.