From e74e4f24dc7dc27ddbda98b6d2317febe2c02df3 Mon Sep 17 00:00:00 2001
From: Kenji Okimoto <okimoto@clear-code.com>
Date: Fri, 26 Oct 2018 17:27:06 +0900
Subject: [PATCH 1/2] Add null check

Sometimes this `cb` is null.
---
 lib/_stream_writable.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index 3bad957912b323..9cfb20776cd82a 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -477,7 +477,7 @@ function afterWrite(stream, state, finished, cb) {
   if (!finished)
     onwriteDrain(stream, state);
   state.pendingcb--;
-  cb();
+  cb && cb();
   finishMaybe(stream, state);
 }
 

From 486fbb404eb3fdf4f9bc547ce66406017979263f Mon Sep 17 00:00:00 2001
From: Kenji Okimoto <okimoto@clear-code.com>
Date: Tue, 30 Oct 2018 10:05:20 +0900
Subject: [PATCH 2/2] Fix style according to suggestion by @devsnek

---
 lib/_stream_writable.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index 9cfb20776cd82a..0096aa27a6f4c8 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -477,7 +477,8 @@ function afterWrite(stream, state, finished, cb) {
   if (!finished)
     onwriteDrain(stream, state);
   state.pendingcb--;
-  cb && cb();
+  if (cb)
+    cb();
   finishMaybe(stream, state);
 }