diff --git a/knockout-transformations/knockout-transformations-tests.ts b/knockout-transformations/knockout-transformations-tests.ts
index 6b15b3ca01..5f132858c9 100644
--- a/knockout-transformations/knockout-transformations-tests.ts
+++ b/knockout-transformations/knockout-transformations-tests.ts
@@ -161,3 +161,46 @@ var indexedTexts: KnockoutObservable<{ [suffixOrPrefix: string]: string[] }> = t
 //     z: ['baz'],
 //     x: ['qux', 'quux']
 // }
+
+
+(() => {
+	var sourceItems: KnockoutObservableArray<number> = ko.observableArray([1, 2, 3, 4, 5]);
+	var asString: KnockoutObservableArray<string>;
+
+	asString = sourceItems.map((x: number) => x.toString());
+
+	asString = sourceItems.map<string>({
+		mapping: (x: number) => x.toString(),
+	});
+
+	asString = sourceItems.map<string>({
+		mapping: (x: number) => x.toString(),
+		disposeItem: (x: string) => console.log('disposing map to', x),
+	});
+
+	asString = sourceItems.map<string>({
+		mappingWithDisposeCallback: (x: number) => ({
+			mappedValue: x.toString(),
+			dispose: () => console.log('disposing map from', x),
+		}),
+	});
+
+	asString = sourceItems.map(x => x.toString());
+
+	asString = sourceItems.map({
+		mapping: x => x.toString(),
+	});
+
+	asString = sourceItems.map<string>({
+		mapping: x => x.toString(),
+		disposeItem: x => console.log('disposing map to', x),
+	});
+
+	asString = sourceItems.map({
+		mappingWithDisposeCallback: x => ({
+			mappedValue: x.toString(),
+			dispose: () => console.log('disposing map from', x),
+		}),
+	});
+
+});
diff --git a/knockout-transformations/knockout-transformations.d.ts b/knockout-transformations/knockout-transformations.d.ts
index b599c7d699..3048e7a0f2 100644
--- a/knockout-transformations/knockout-transformations.d.ts
+++ b/knockout-transformations/knockout-transformations.d.ts
@@ -5,8 +5,27 @@
 
 /// <reference path="../knockout/knockout.d.ts" />
 
+declare module KnockoutTransformations {
+    interface Mapping<T, TResult> {
+        (value: T): TResult;
+    }
+    interface MappingOption<T, TResult> {
+        mapping: Mapping<T, TResult>;
+        disposeItem?: (item: TResult) => void;
+    }
+    interface MappingWithDisposeCallbackOption<T, TResult> {
+        mappingWithDisposeCallback: (value: T) => {
+            mappedValue: TResult;
+            dispose: () => void;
+        };
+    }
+}
+
 interface KnockoutObservableArrayFunctions<T> {
-    map<TResult>(mapping: (value: T) => TResult): KnockoutObservableArray<TResult>;
+    map<TResult>(mapping: KnockoutTransformations.Mapping<T, TResult>): KnockoutObservableArray<TResult>;
+    map<TResult>(mapping: KnockoutTransformations.MappingOption<T, TResult>): KnockoutObservableArray<TResult>;
+    map<TResult>(mapping: KnockoutTransformations.MappingWithDisposeCallbackOption<T, TResult>): KnockoutObservableArray<TResult>;
+
     filter(predicate: (value: T) => boolean): KnockoutObservableArray<T>;
     sortBy(sorter: (value: T, descending: (sorter: any) => any) => any): KnockoutObservableArray<T>;
     indexBy(indexer: (value: T) => string): KnockoutObservable<{ [index: string]: T[] }>;