nodejs · Trott · Feb 28, 2021 · Feb 24, 2021
diff --git 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
@@ -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
@@ -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
@@ -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',

diff --git a/test/parallel/test-bootstrap-modules.js b/test/parallel/test-bootstrap-modules.js
@@ -98,6 +98,7 @@ const expectedModules = new Set([
  'NativeModule internal/streams/readable',
  'NativeModule internal/streams/state',
  'NativeModule internal/streams/transform',
+  'NativeModule internal/streams/utils',
  'NativeModule internal/streams/writable',
  'NativeModule internal/timers',
  'NativeModule internal/url',