diff --git a/Foundation/CPArray+KVO.j b/Foundation/CPArray+KVO.j
index ad05ef8c6..afe962229 100644
--- a/Foundation/CPArray+KVO.j
+++ b/Foundation/CPArray+KVO.j
@@ -428,7 +428,9 @@ var avgOperator,
     maxOperator,
     minOperator,
     countOperator,
-    sumOperator;
+    sumOperator,
+    distinctUnionOfObjectsOperator,
+    unionOfObjectsOperator;
 
 kvoOperators["avg"] = function avgOperator(self, _cmd, param)
 {
@@ -495,6 +497,18 @@ kvoOperators["sum"] = function sumOperator(self, _cmd, param)
     return sum;
 }
 
+kvoOperators["distinctUnionOfObjects"] = function distinctUnionOfObjectsOperator(self, _cmd, param)
+{
+    var objects = [self valueForKeyPath:param];
+
+    return [[CPSet setWithArray:objects] allObjects];
+}
+
+kvoOperators["unionOfObjects"] = function unionOfObjectsOperator(self, _cmd, param)
+{
+    return [self valueForKeyPath:param];
+}
+
 @implementation CPArray (KeyValueObserving)
 
 - (void)addObserver:(id)anObserver toObjectsAtIndexes:(CPIndexSet)indexes forKeyPath:(CPString)aKeyPath options:(unsigned)options context:(id)context