diff --git a/d3/d3-tests.ts b/d3/d3-tests.ts
index 1a2b5f1c5..51c51f608 100644
--- a/d3/d3-tests.ts
+++ b/d3/d3-tests.ts
@@ -47,6 +47,37 @@ function testPieChart() {
     });
 }
 
+function testMapConstructor() {
+    //No arg constructor
+    var emptyMap: D3.Map<any> = d3.map();
+
+    //Object constructor
+    var object:{[key: string]: number } = {a: 1, b: 2, c: 3};
+    var objectMap: D3.Map<number> = d3.map<number>(object);
+
+    //Array constructor
+    var numberArray: number[] = [1, 2, 3]
+    var numberArrayMap: D3.Map<number> = d3.map<number>(numberArray);
+
+    //Array with keyFn constructor
+    var objectArray: {key: string}[] = [{key: "v1"}, {key: "v2"}, {key: "v3"}];
+    var indexes: number[] = [];
+    //keyFn with index
+    var objectArrayMap1: D3.Map<{key: string}>
+            = d3.map<{key: string}>(objectArray, (o: {key: string}, index: number) => {
+        indexes.push(index);
+        return o.key;
+    });
+    //keyFn without index
+    var objectArrayMap2: D3.Map<{key: string}>
+            = d3.map<{key: string}>(objectArray, (o: {key: string}) => {
+        return o.key;
+    });
+
+    //Map constructor
+    var duplicateMap: D3.Map<number> = d3.map(numberArrayMap);
+}
+
 //Example from http://bl.ocks.org/3887051
 interface GroupedData {
     State: string;
diff --git a/d3/d3.d.ts b/d3/d3.d.ts
index 8569ab3f8..be4032921 100644
--- a/d3/d3.d.ts
+++ b/d3/d3.d.ts
@@ -549,10 +549,17 @@ declare module D3 {
         functor<R,T>(value: (p : R) => T): (p : R) => T;
         functor<T>(value: T): (p : any) => T;
 
-        map(): Map<any>;
-        set(): Set<any>;
-        map<T>(object: {[key: string]: T; }): Map<T>;
-        set<T>(array: T[]): Set<T>;
+        map: {
+            (): Map<any>;
+            <T>(object: {[key: string]: T; }): Map<T>;
+            <T>(map: Map<T>): Map<T>;
+            <T>(array: T[]): Map<T>;
+            <T>(array: T[], keyFn: (object: T, index?: number) => string): Map<T>;
+        };
+        set: {
+            (): Set<any>;
+            <T>(array: T[]): Set<T>;
+        };
         dispatch(...types: string[]): Dispatch;
         rebind(target: any, source: any, ...names: any[]): any;
         requote(str: string): string;