Add basic type definitions for express 4.x

compression/compression.d.ts

@@ -0,0 +1,20 @@
+// Type definitions for compression
+// Project: https://github.com/expressjs/compression
+// Definitions by: Santi Albo <https://github.com/santialbo/>
+// DefinitelyTyped: https://github.com/borisyankov/DefinitelyTyped
+
+/// <reference path="../express/express.d.ts" />
+
+declare module "compression" {
+    import express = require('express');
+
+    module e {
+        interface CompressionOptions  {
+            threshold?: number;
+            filter?: Function;
+        }
+    }
+
+    function e(options?: e.CompressionOptions): express.RequestHandler;
+    export = e;
+}