diff --git a/merge-stream/merge-stream-tests.ts b/merge-stream/merge-stream-tests.ts
index e0c744953e..140013eb9c 100644
--- a/merge-stream/merge-stream-tests.ts
+++ b/merge-stream/merge-stream-tests.ts
@@ -11,3 +11,9 @@ var merged = merge(stream1, stream2);
 
 var stream3 = new Stream();
 merged.add(stream3);
+
+var stream4 = new Stream();
+var stream5 = new Stream();
+merged.add([stream4, stream5]);
+
+merged.isEmpty();
diff --git a/merge-stream/merge-stream.d.ts b/merge-stream/merge-stream.d.ts
index 6dfffdb958..d2f8c756e6 100644
--- a/merge-stream/merge-stream.d.ts
+++ b/merge-stream/merge-stream.d.ts
@@ -1,14 +1,15 @@
-// Type definitions for merge-stream
+// Type definitions for merge-stream v1.0.0
 // Project: https://github.com/grncdr/merge-stream
-// Definitions by: Keita Kagurazaka <https://github.com/k-kagurazaka>
-// Definitions: https://github.com/borisyankov/DefinitelyTyped
+// Definitions by: Keita Kagurazaka <https://github.com/k-kagurazaka>, Tom X. Tobin <http://tomxtobin.com/>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 /// <reference path="../node/node.d.ts"/>
 
 declare module "merge-stream" {
-
     interface IMergedStream extends NodeJS.ReadWriteStream {
-        add: (source: NodeJS.ReadableStream) => IMergedStream;
+        add(source: NodeJS.ReadableStream): IMergedStream;
+        add(source: NodeJS.ReadableStream[]): IMergedStream;
+        isEmpty(): boolean;
     }
 
     function merge<T extends NodeJS.ReadableStream>(...streams: T[]): IMergedStream;