stream: cleanup a few minor details in stream/iter

Author: jasnell

lib/internal/streams/iter/broadcast.js

@@ -727,6 +727,7 @@ function isBroadcastable(value) {
 }
 
 const Broadcast = {
+  __proto__: null,
   from(input, options) {
     if (isBroadcastable(input)) {
       const bc = input[broadcastProtocol](options);

lib/internal/streams/iter/from.js

@@ -57,10 +57,7 @@ const FROM_BATCH_SIZE = 128;
  * @returns {boolean}
  */
 function isPrimitiveChunk(value) {
-  if (typeof value === 'string') return true;
-  if (isArrayBuffer(value)) return true;
-  if (ArrayBufferIsView(value)) return true;
-  return false;
+  return typeof value === 'string' || isArrayBuffer(value) || ArrayBufferIsView(value);
 }
 
 /**

lib/internal/streams/iter/share.js

@@ -647,6 +647,7 @@ function isSyncShareable(value) {
 }
 
 const Share = {
+  __proto__: null,
   from(input, options) {
     if (isShareable(input)) {
       const result = input[shareProtocol](options);
@@ -665,6 +666,7 @@ const Share = {
 };
 
 const SyncShare = {
+  __proto__: null,
   fromSync(input, options) {
     if (isSyncShareable(input)) {
       const result = input[shareSyncProtocol](options);

lib/internal/streams/iter/transform.js

@@ -1,6 +1,6 @@
 'use strict';
 
-// New Streams API - Compression / Decompression Transforms
+// Compression / Decompression Transforms
 //
 // Creates bare native zlib handles via internalBinding('zlib'), bypassing
 // the stream.Transform / ZlibBase / EventEmitter machinery entirely.

lib/internal/streams/iter/types.js

@@ -1,11 +1,5 @@
 'use strict';
 
-// New Streams API - Protocol Symbols
-//
-// These symbols allow objects to participate in streaming.
-// Using Symbol.for() allows third-party code to implement protocols
-// without importing these symbols directly.
-
 const {
   SymbolFor,
 } = primordials;

lib/internal/streams/iter/utils.js

@@ -1,24 +1,26 @@
 'use strict';
 
-// New Streams API - Utility Functions
-
 const {
-  Array,
   ArrayPrototypeSlice,
+  TypedArrayPrototypeGetBuffer,
   TypedArrayPrototypeGetByteLength,
-  TypedArrayPrototypeSet,
+  TypedArrayPrototypeGetByteOffset,
   Uint8Array,
 } = primordials;
 
 const { TextEncoder } = require('internal/encoding');
 const {
   codes: {
     ERR_INVALID_ARG_TYPE,
-    ERR_INVALID_ARG_VALUE,
   },
 } = require('internal/errors');
+
+const { Buffer } = require('buffer');
+
 const { isUint8Array } = require('internal/util/types');
 
+const { validateOneOf } = require('internal/validators');
+
 // Shared TextEncoder instance for string conversion.
 const encoder = new TextEncoder();
 
@@ -55,6 +57,7 @@ function toUint8Array(chunk) {
  * @returns {boolean}
  */
 function allUint8Array(chunks) {
+  // Ok, well, kind of. This is more a check for "no strings"...
   for (let i = 0; i < chunks.length; i++) {
     if (typeof chunks[i] === 'string') return false;
   }
@@ -67,28 +70,11 @@ function allUint8Array(chunks) {
  * @returns {Uint8Array}
  */
 function concatBytes(chunks) {
-  if (chunks.length === 0) {
-    return new Uint8Array(0);
-  }
-  if (chunks.length === 1) {
-    return chunks[0];
-  }
-
-  const len = chunks.length;
-  const lengths = new Array(len);
-  let total = 0;
-  for (let i = 0; i < len; i++) {
-    const l = TypedArrayPrototypeGetByteLength(chunks[i]);
-    lengths[i] = l;
-    total += l;
-  }
-  const result = new Uint8Array(total);
-  let offset = 0;
-  for (let i = 0; i < len; i++) {
-    TypedArrayPrototypeSet(result, chunks[i], offset);
-    offset += lengths[i];
-  }
-  return result;
+  const buf = Buffer.concat(chunks);
+  return new Uint8Array(
+    TypedArrayPrototypeGetBuffer(buf),
+    TypedArrayPrototypeGetByteOffset(buf),
+    TypedArrayPrototypeGetByteLength(buf));
 }
 
 /**
@@ -154,14 +140,12 @@ function parsePullArgs(args) {
  * @param {string} value
  */
 function validateBackpressure(value) {
-  if (value !== 'strict' &&
-      value !== 'block' &&
-      value !== 'drop-oldest' &&
-      value !== 'drop-newest') {
-    throw new ERR_INVALID_ARG_VALUE(
-      'options.backpressure', value,
-      'must be "strict", "block", "drop-oldest", or "drop-newest"');
-  }
+  validateOneOf(value, 'options.backpressure', [
+    'strict',
+    'block',
+    'drop-oldest',
+    'drop-newest',
+  ]);
 }
 
 module.exports = {