Fixed opening for memory leak bug using deregister method on service and scope.$on('$destroy') in pagination link function

Author: kyletheninja

src/directives/pagination/dirPagination.js

@@ -62,6 +62,9 @@
                     // Now that we have access to the `scope` we can interpolate any expression given in the paginationId attribute and
                     // potentially register a new ID if it evaluates to a different value than the rawId.
                     var paginationId = $parse(attrs.paginationId)(scope) || attrs.paginationId || DEFAULT_ID;
+                    // In case rawId != paginationId we deregister using rawId for the sake of general cleanliness
+                    // before registering using paginationId
+                    paginationService.deregisterInstance(rawId);
                     paginationService.registerInstance(paginationId);
 
                     var repeatExpression;
@@ -115,6 +118,12 @@
 
                     // Delegate to the link function returned by the new compilation of the ng-repeat
                     compiled(scope);
+                    
+                    // When the scope is destroyed, we make sure to remove the reference to it in paginationService
+                    // so that it can be properly garbage collected
+                    scope.$on('$destroy', function destroyDirPagination() {
+                    	paginationService.deregisterInstance(paginationId);
+                    });
                 };
             }
         }; 
@@ -351,6 +360,10 @@
             }
         };
 
+        this.deregisterInstance = function(instanceId) {
+        	delete instances[instanceId];
+        };
+        
         this.isRegistered = function(instanceId) {
             return (typeof instances[instanceId] !== 'undefined');
         };
@@ -410,4 +423,4 @@
             };
         };
     });
-})();
+})();