From 8876ff6b1cee3a8996dbd0c73cfcb9ee04a85d44 Mon Sep 17 00:00:00 2001
From: Rich Trott <rtrott@gmail.com>
Date: Wed, 24 Feb 2021 11:30:50 -0800
Subject: [PATCH] stream: move duplicated code to an internal module

Create a utils module for isIterable(), isReadable(), and isStream().
---
 lib/internal/streams/pipeline.js | 27 ++++++---------------------
 lib/internal/streams/utils.js    | 32 ++++++++++++++++++++++++++++++++
 lib/stream/promises.js           | 27 +++++----------------------
 node.gyp                         |  1 +
 4 files changed, 44 insertions(+), 43 deletions(-)
 create mode 100644 lib/internal/streams/utils.js

diff --git a/lib/internal/streams/pipeline.js b/lib/internal/streams/pipeline.js
index a34a55d562304c..5215d986ef1f1c 100644
--- a/lib/internal/streams/pipeline.js
+++ b/lib/internal/streams/pipeline.js
@@ -11,7 +11,6 @@ const {
   FunctionPrototypeCall,
   ReflectApply,
   SymbolAsyncIterator,
-  SymbolIterator,
 } = primordials;
 
 let eos;
@@ -27,6 +26,12 @@ const {
 
 const { validateCallback } = require('internal/validators');
 
+const {
+  isIterable,
+  isReadable,
+  isStream,
+} = require('internal/streams/utils');
+
 let EE;
 let PassThrough;
 let Readable;
@@ -82,26 +87,6 @@ function popCallback(streams) {
   return ArrayPrototypePop(streams);
 }
 
-function isReadable(obj) {
-  return !!(obj && typeof obj.pipe === 'function');
-}
-
-function isWritable(obj) {
-  return !!(obj && typeof obj.write === 'function');
-}
-
-function isStream(obj) {
-  return isReadable(obj) || isWritable(obj);
-}
-
-function isIterable(obj, isAsync) {
-  if (!obj) return false;
-  if (isAsync === true) return typeof obj[SymbolAsyncIterator] === 'function';
-  if (isAsync === false) return typeof obj[SymbolIterator] === 'function';
-  return typeof obj[SymbolAsyncIterator] === 'function' ||
-    typeof obj[SymbolIterator] === 'function';
-}
-
 function makeAsyncIterable(val) {
   if (isIterable(val)) {
     return val;
diff --git a/lib/internal/streams/utils.js b/lib/internal/streams/utils.js
new file mode 100644
index 00000000000000..08c196802780b8
--- /dev/null
+++ b/lib/internal/streams/utils.js
@@ -0,0 +1,32 @@
+'use strict';
+
+const {
+  SymbolAsyncIterator,
+  SymbolIterator,
+} = primordials;
+
+function isReadable(obj) {
+  return !!(obj && typeof obj.pipe === 'function');
+}
+
+function isWritable(obj) {
+  return !!(obj && typeof obj.write === 'function');
+}
+
+function isStream(obj) {
+  return isReadable(obj) || isWritable(obj);
+}
+
+function isIterable(obj, isAsync) {
+  if (!obj) return false;
+  if (isAsync === true) return typeof obj[SymbolAsyncIterator] === 'function';
+  if (isAsync === false) return typeof obj[SymbolIterator] === 'function';
+  return typeof obj[SymbolAsyncIterator] === 'function' ||
+    typeof obj[SymbolIterator] === 'function';
+}
+
+module.exports = {
+  isIterable,
+  isReadable,
+  isStream,
+};
diff --git a/lib/stream/promises.js b/lib/stream/promises.js
index 90d6b1244bd380..027579b878dbf7 100644
--- a/lib/stream/promises.js
+++ b/lib/stream/promises.js
@@ -3,8 +3,6 @@
 const {
   ArrayPrototypePop,
   Promise,
-  SymbolAsyncIterator,
-  SymbolIterator,
 } = primordials;
 
 const {
@@ -15,29 +13,14 @@ const {
   validateAbortSignal,
 } = require('internal/validators');
 
+const {
+  isIterable,
+  isStream,
+} = require('internal/streams/utils');
+
 let pl;
 let eos;
 
-function isReadable(obj) {
-  return !!(obj && typeof obj.pipe === 'function');
-}
-
-function isWritable(obj) {
-  return !!(obj && typeof obj.write === 'function');
-}
-
-function isStream(obj) {
-  return isReadable(obj) || isWritable(obj);
-}
-
-function isIterable(obj, isAsync) {
-  if (!obj) return false;
-  if (isAsync === true) return typeof obj[SymbolAsyncIterator] === 'function';
-  if (isAsync === false) return typeof obj[SymbolIterator] === 'function';
-  return typeof obj[SymbolAsyncIterator] === 'function' ||
-    typeof obj[SymbolIterator] === 'function';
-}
-
 function pipeline(...streams) {
   if (!pl) pl = require('internal/streams/pipeline');
   return new Promise((resolve, reject) => {
diff --git a/node.gyp b/node.gyp
index cba5c0113de42e..63c8c50987b20e 100644
--- a/node.gyp
+++ b/node.gyp
@@ -263,6 +263,7 @@
       'lib/internal/streams/state.js',
       'lib/internal/streams/pipeline.js',
       'lib/internal/streams/end-of-stream.js',
+      'lib/internal/streams/utils.js',
       'deps/v8/tools/splaytree.js',
       'deps/v8/tools/codemap.js',
       'deps/v8/tools/consarray.js',