From 757de539bf5773c4ba10286d310c18b99d228bdd Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Sat, 21 Sep 2019 01:29:41 +0200
Subject: [PATCH 1/4] stream: _write optional when _writev

When implementing _writev, _write should be optional.
---
 doc/api/stream.md                   | 11 ++++++-----
 lib/_stream_writable.js             |  6 +++++-
 test/parallel/test-stream-writev.js |  9 +++++++++
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/doc/api/stream.md b/doc/api/stream.md
index 1f0f08a7b86a7f..68a0720f3399e4 100644
--- a/doc/api/stream.md
+++ b/doc/api/stream.md
@@ -1667,8 +1667,8 @@ const myWritable = new Writable({
 The `stream.Writable` class is extended to implement a [`Writable`][] stream.
 
 Custom `Writable` streams *must* call the `new stream.Writable([options])`
-constructor and implement the `writable._write()` method. The
-`writable._writev()` method *may* also be implemented.
+constructor and implement the `writable._write()` and/or `writable._writev()`
+method.
 
 #### Constructor: new stream.Writable([options])
 <!-- YAML
@@ -1770,7 +1770,8 @@ const myWritable = new Writable({
   argument) when processing is complete for the supplied chunk.
 
 All `Writable` stream implementations must provide a
-[`writable._write()`][stream-_write] method to send data to the underlying
+[`writable._write()`][stream-_write] and/or
+[`writable._writev()`][stream-_writev] method to send data to the underlying
 resource.
 
 [`Transform`][] streams provide their own implementation of the
@@ -1813,8 +1814,8 @@ This function MUST NOT be called by application code directly. It should be
 implemented by child classes, and called by the internal `Writable` class
 methods only.
 
-The `writable._writev()` method may be implemented in addition to
-`writable._write()` in stream implementations that are capable of processing
+The `writable._writev()` method may be implemented in addition or alternatively
+to `writable._write()` in stream implementations that are capable of processing
 multiple chunks of data at once. If implemented, the method will be called with
 all chunks of data currently buffered in the write queue.
 
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index 4cb3be5c008e9e..d61c1557195762 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -558,7 +558,11 @@ function clearBuffer(stream, state) {
 }
 
 Writable.prototype._write = function(chunk, encoding, cb) {
-  cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
+  if (this._writev) {
+    this._writev([{ chunk, encoding }], cb);
+  } else {
+    cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
+  }
 };
 
 Writable.prototype._writev = null;
diff --git a/test/parallel/test-stream-writev.js b/test/parallel/test-stream-writev.js
index 1123e66ddc5767..f9e9d985a81f1d 100644
--- a/test/parallel/test-stream-writev.js
+++ b/test/parallel/test-stream-writev.js
@@ -119,3 +119,12 @@ function test(decode, uncork, multi, next) {
     next();
   });
 }
+
+{
+  const w = new stream.Writable({
+    writev: function(chunks, cb) {
+      cb();
+    }
+  });
+  w.write('asd', common.mustCall());
+}

From ee8d27979a7acf2f275965ba90dd1f0d9294d183 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Sat, 21 Sep 2019 01:43:06 +0200
Subject: [PATCH 2/4] fixup

---
 test/parallel/test-stream-writev.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/parallel/test-stream-writev.js b/test/parallel/test-stream-writev.js
index f9e9d985a81f1d..7aba543f0732f6 100644
--- a/test/parallel/test-stream-writev.js
+++ b/test/parallel/test-stream-writev.js
@@ -122,9 +122,9 @@ function test(decode, uncork, multi, next) {
 
 {
   const w = new stream.Writable({
-    writev: function(chunks, cb) {
+    writev: common.mustCall(function(chunks, cb) {
       cb();
-    }
+    })
   });
   w.write('asd', common.mustCall());
 }

From c0395158eaae82fc083ec3a1477cc75ae3711b08 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Sat, 21 Sep 2019 01:44:33 +0200
Subject: [PATCH 3/4] fixup

---
 doc/api/stream.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/doc/api/stream.md b/doc/api/stream.md
index 68a0720f3399e4..1447f1b51eda30 100644
--- a/doc/api/stream.md
+++ b/doc/api/stream.md
@@ -1757,6 +1757,12 @@ const myWritable = new Writable({
 ```
 
 #### writable.\_write(chunk, encoding, callback)
+<!-- YAML
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/29639
+    description: _write is optional when providing _writev.
+-->
 
 * `chunk` {Buffer|string|any} The `Buffer` to be written, converted from the
   `string` passed to [`stream.write()`][stream-write]. If the stream's

From 6c514271b3070b4f4c58bdb6160934e34967af3c Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Sat, 21 Sep 2019 07:59:50 +0200
Subject: [PATCH 4/4] Update doc/api/stream.md

Co-Authored-By: Luigi Pinca <luigipinca@gmail.com>
---
 doc/api/stream.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/api/stream.md b/doc/api/stream.md
index 1447f1b51eda30..4ae7ac38079ef7 100644
--- a/doc/api/stream.md
+++ b/doc/api/stream.md
@@ -1761,7 +1761,7 @@ const myWritable = new Writable({
 changes:
   - version: REPLACEME
     pr-url: https://github.com/nodejs/node/pull/29639
-    description: _write is optional when providing _writev.
+    description: _write() is optional when providing _writev().
 -->
 
 * `chunk` {Buffer|string|any} The `Buffer` to be written, converted from the