diff --git a/blob-stream/blob-stream-tests.ts b/blob-stream/blob-stream-tests.ts
index 574dfc044..fab093206 100644
--- a/blob-stream/blob-stream-tests.ts
+++ b/blob-stream/blob-stream-tests.ts
@@ -3,5 +3,5 @@
 
 var bl = require('blob-stream');
 
-var blob = bl.toBlob("aplication/PDF");
+var blob = bl.toBlob();
 var brl = bl.toBlobURL("app/JSON");
diff --git a/blob-stream/blob-stream.d.ts b/blob-stream/blob-stream.d.ts
index 5c62155b6..b55cd13c6 100644
--- a/blob-stream/blob-stream.d.ts
+++ b/blob-stream/blob-stream.d.ts
@@ -10,8 +10,8 @@ declare function BlobStream(): BlobStream.IBlobStream;
 declare module BlobStream {
 
     interface IBlobStream extends NodeJS.WritableStream{
-        toBlob(type: string): Blob;
-        toBlobURL(type: string): string;
+        toBlob(type?: string): Blob;
+        toBlobURL(type?: string): string;
     }
 }