diff --git a/knockout.projections/knockout.projections-tests.ts b/knockout.projections/knockout.projections-tests.ts
index 3d479e7ac..138d36946 100644
--- a/knockout.projections/knockout.projections-tests.ts
+++ b/knockout.projections/knockout.projections-tests.ts
@@ -26,3 +26,39 @@ sourceItems.push(9);
 
 sourceItems.push(10);
 // evenSquares now contains [36, 16, 4, 100]
+
+// Testing mapping options
+
+interface IComplexItem {
+    value: string;
+    dispose(): void;
+}
+
+var complexItems = sourceItems.map({
+    mapping: x => {
+        var item: IComplexItem = {
+            value: (x * x).toString(),
+            dispose: () => { }
+        };
+
+        return item;
+    },
+    disposeItem: (item: IComplexItem) => item.dispose()
+});
+
+var complexItems2 = sourceItems.map({
+    mappingWithDisposeCallback: x => {
+        return {
+            mappedValue: (x * x).toString(),
+            dispose: () => { }
+        };
+    }
+});
+
+// Test disposal
+
+evenSquares.dispose();
+
+complexItems.dispose();
+
+complexItems2.dispose();
diff --git a/knockout.projections/knockout.projections.d.ts b/knockout.projections/knockout.projections.d.ts
index 77f3bf0ec..e1443478a 100644
--- a/knockout.projections/knockout.projections.d.ts
+++ b/knockout.projections/knockout.projections.d.ts
@@ -5,8 +5,21 @@
 
 /// <reference path="../knockout/knockout.d.ts" />
 
+interface KnockoutMappedObservableArray<T> extends KnockoutObservableArray<T>, KnockoutSubscription {
+}
+
 interface KnockoutObservableArrayFunctions<T> {
-
-    map<TResult>(mapping: (value: T) => TResult): KnockoutObservableArray<TResult>;
-    filter(predicate: (value: T) => boolean): KnockoutObservableArray<T>;
+    map<TResult>(mappingOptions: {
+        mappingWithDisposeCallback: (value: T) => {
+            mappedValue: TResult;
+            dispose: () => void;
+        };
+    }): KnockoutMappedObservableArray<TResult>;
+    map<TResult>(mappingOptions: {
+        mapping: (value: T) => TResult;
+        disposeItem?: (mappedItem: TResult) => void;
+    }): KnockoutMappedObservableArray<TResult>;
+    map<TResult>(mappingOptions: (value: T) => TResult): KnockoutMappedObservableArray<TResult>;
+    
+    filter(predicate: (value: T) => boolean): KnockoutMappedObservableArray<T>;
 }