stream: Duplex re-use Writable properties

Instead of reimplementing Writable properties, fetch them from the Writable prototype.

Author: ronag

lib/_stream_duplex.js

@@ -71,7 +71,20 @@ function Duplex(options){
 }
 
 ObjectDefineProperties(Duplex.prototype,{
-writable: ObjectGetOwnPropertyDescriptor(Writable.prototype,'writable'),
+writable:
+ObjectGetOwnPropertyDescriptor(Writable.prototype,'writable'),
+writableHighWaterMark:
+ObjectGetOwnPropertyDescriptor(Writable.prototype,'writableHighWaterMark'),
+writableBuffer:
+ObjectGetOwnPropertyDescriptor(Writable.prototype,'writableBuffer'),
+writableLength:
+ObjectGetOwnPropertyDescriptor(Writable.prototype,'writableLength'),
+writableFinished:
+ObjectGetOwnPropertyDescriptor(Writable.prototype,'writableFinished'),
+writableCorked:
+ObjectGetOwnPropertyDescriptor(Writable.prototype,'writableCorked'),
+writableEnded:
+ObjectGetOwnPropertyDescriptor(Writable.prototype,'writableEnded'),
 
 destroyed: {
 get(){
@@ -89,41 +102,5 @@ ObjectDefineProperties(Duplex.prototype,{
 this._writableState.destroyed=value;
 }
 }
-},
-
-writableHighWaterMark: {
-get(){
-returnthis._writableState&&this._writableState.highWaterMark;
-}
-},
-
-writableBuffer: {
-get(){
-returnthis._writableState&&this._writableState.getBuffer();
-}
-},
-
-writableLength: {
-get(){
-returnthis._writableState&&this._writableState.length;
-}
-},
-
-writableFinished: {
-get(){
-returnthis._writableState ? this._writableState.finished : false;
-}
-},
-
-writableCorked: {
-get(){
-returnthis._writableState ? this._writableState.corked : 0;
-}
-},
-
-writableEnded: {
-get(){
-returnthis._writableState ? this._writableState.ending : false;
-}
 }
 });