Fix exporting class instead of factory for ParallelTransformStream

README.md

@@ -53,10 +53,10 @@ Emitted: 3
 
 #### throughParallel([options], [transform], [flush])
 
-* `options`: Options to pass to the `Transform` stream plus one specific option:
+* `options`: Options to pass to the [`Transform`](http://nodejs.org/api/stream.html#stream_new_stream_transform_options) stream plus one specific option:
   *  `concurrency`: defaults to `2` and specifies how many tasks can run in parallel
-* `transform`: the `_transform` function
-* `flush`: the `_flush` function
+* `transform`: the [`_transform`](http://nodejs.org/api/stream.html#stream_transform_transform_chunk_encoding_callback) function.
+* `flush`: the [`_flush`](http://nodejs.org/api/stream.html#stream_transform_flush_callback) function.
 
 #### throughParallel.obj([options], [transform], [flush])
 

parallelTransformStream.js

@@ -44,15 +44,15 @@ ParallelTransformStream.prototype._createCallback =
   function _createCallback(item) {
     var self = this;
     return function(err, chunk) {
-      if(chunk) {
-        item.chunks.push(chunk);
-      }
-      item.completed = true;
-
       if(err) {
         self.emit('error', err);
         item.chunks = [];
+      } else {
+        if (chunk) {
+          item.chunks.push(chunk);
+        }
       }
+      item.completed = true;
       self._drainBuffer();
     };
   };
@@ -92,7 +92,5 @@ ParallelTransformStream.prototype._flush =
     }
   };
 
-module.exports = function(transform, concurrency) {
-  return new ParallelTransformStream(transform, concurrency);
-};
+module.exports = ParallelTransformStream;