stream: add writableFinished

add a new getter to duplex stream to replace the property `this
.writableState.finished` of the object that inherited duplex.

Refs: https://github.com/nodejs/node/issues/445

PR-URL: https://github.com/nodejs/node/pull/28007
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Rich Trott <rtrott@gmail.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/_stream_duplex.js b/lib/_stream_duplex.js
index 49520c4074..d20877e921 100644
--- a/lib/_stream_duplex.js
+++ b/lib/_stream_duplex.js
@@ -98,6 +98,16 @@ Object.defineProperty(Duplex.prototype, 'writableLength', {
   }
 });
 
+Object.defineProperty(Duplex.prototype, 'writableFinished', {
+  // Making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get() {
+    return this._writableState.finished;
+  }
+});
+
 // The no-half-open enforcer
 function onend() {
   // If the writable side ended, then we're ok.