performance improvement for exposeAsideWhen directive that also fixes…

… issue ionic-team#3600

js/angular/directive/exposeAsideWhen.js

@@ -39,36 +39,37 @@
  * For a complete side menu example, see the
  * {@link ionic.directive:ionSideMenus} documentation.
  */
-IonicModule.directive('exposeAsideWhen', ['$window', function($window) {
+
+IonicModule.directive('exposeAsideWhen', ['$window', function($window) { 
   return {
     restrict: 'A',
     require: '^ionSideMenus',
     link: function($scope, $element, $attr, sideMenuCtrl) {
 
+      // Setup a match media query listener that triggers a ui change only when a change
+      // in media matching status occurs
+      var mq = $attr.exposeAsideWhen == 'large' ? '(min-width:768px)' : $attr.exposeAsideWhen;
+      var mql = $window.matchMedia(mq);
+      mql.addListener(function (mql) {
+        onResize();
+      })
+
       function checkAsideExpose() {
         var mq = $attr.exposeAsideWhen == 'large' ? '(min-width:768px)' : $attr.exposeAsideWhen;
         sideMenuCtrl.exposeAside($window.matchMedia(mq).matches);
         sideMenuCtrl.activeAsideResizing(false);
       }
 
       function onResize() {
+        debouncedCheck();        
         sideMenuCtrl.activeAsideResizing(true);
-        debouncedCheck();
       }
 
       var debouncedCheck = ionic.debounce(function() {
         $scope.$apply(checkAsideExpose);
       }, 300, false);
 
       $scope.$evalAsync(checkAsideExpose);
-
-      ionic.on('resize', onResize, $window);
-
-      $scope.$on('$destroy', function() {
-        ionic.off('resize', onResize, $window);
-      });
-
     }
   };
-}]);
-
+}]);