Update index.js

Author: Joe Podwys

index.js

@@ -94,24 +94,24 @@ function compression(options) {
 
       if (!this._header) {
         // estimate the length
-        if (!this.getHeader('Content-Length'), cb) {
-          length = chunkLength(chunk, encoding, cb)
+        if (!this.getHeader('Content-Length')) {
+          length = chunkLength(chunk, encoding)
         }
 
         this._implicitHeader()
       }
 
       if (!stream) {
-        return end.call(this, chunk, encoding)
+        return end.call(this, chunk, encoding, cb)
       }
 
       // mark ended
       ended = true
 
       // write Buffer for Node.js 0.8
       return chunk
-        ? stream.end(new Buffer(chunk, encoding))
-        : stream.end()
+        ? stream.end(new Buffer(chunk, encoding), cb)
+        : stream.end(null, cb)
     };
 
     res.on = function(type, listener){