add ArrayBuffer.prototype.{ transfer, transferToFixedLength } and s…

…upport transferring of `ArrayBuffer`s via `structuredClone` to engines with `MessageChannel`

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Changelog
 ##### Unreleased
+- Added `ArrayBuffer.prototype.{ transfer, transferToFixedLength }` and support transferring of `ArrayBuffer`s via `structuredClone` to engines with `MessageChannel`
 - Fully forced polyfilling of [the TC39 `Observable` proposal](https://github.com/tc39/proposal-observable) because of incompatibility with [the new WHATWG `Observable` proposal](https://github.com/WICG/observable)
 - Added an extra workaround of errors with exotic environment objects in `Symbol` polyfill, [#1289](https://github.com/zloirock/core-js/issues/1289)
 - Compat data improvements:

README.md

@@ -2391,7 +2391,7 @@ console.log(view.getFloat16(0)); // => 1.3369140625
 ```
 
 ##### [`ArrayBuffer.prototype.transfer` and friends](#https://github.com/tc39/proposal-arraybuffer-transfer)[⬆](#index)
-Note: **`ArrayBuffer.prototype.{ transfer, transferToFixedLength }` polyfilled only in runtime with native `structuredClone` with `ArrayBuffer` transfer support.**
+Note: **`ArrayBuffer.prototype.{ transfer, transferToFixedLength }` polyfilled only in runtime with native `structuredClone` with `ArrayBuffer` transfer or `MessageChannel` support.**
 Modules [`esnext.array-buffer.detached`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array-buffer.detached.js), [`esnext.array-buffer.transfer`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array-buffer.transfer.js), [`esnext.array-buffer.transfer-to-fixed-length`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array-buffer.transfer-to-fixed-length.js).
 ```js
 class ArrayBuffer {
@@ -3222,7 +3222,7 @@ structuredClone(new WeakMap()); // => DataCloneError on non-serializable types
 ```
 ##### Caveats when using `structuredClone` polyfill:[⬆](#index)
 
-* `ArrayBuffer` instances and many platform types cannot be transferred in most engines since we have no way to polyfill this behavior, however `.transfer` option works for some platform types. I recommend avoiding this option.
+* Many platform types cannot be transferred in most engines since we have no way to polyfill this behavior, however `.transfer` option works for some platform types. I recommend avoiding this option.
 * Some specific platform types can't be cloned in old engines. Mainly it's very specific types or very old engines, but here are some exceptions. For example, we have no sync way to clone `ImageBitmap` in Safari 14.0- or Firefox 83-, so it's recommended to look to the [polyfill source](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/web.structured-clone.js) if you wanna clone something specific.
 
 #### Base64 utility methods[⬆](#index)

packages/core-js/internals/array-buffer-transfer.js

@@ -5,12 +5,13 @@ var uncurryThisAccessor = require('../internals/function-uncurry-this-accessor')
 var toIndex = require('../internals/to-index');
 var isDetached = require('../internals/array-buffer-is-detached');
 var arrayBufferByteLength = require('../internals/array-buffer-byte-length');
-var PROPER_TRANSFER = require('../internals/structured-clone-proper-transfer');
+var detachViaMessageChannel = require('../internals/detach-via-message-channel');
+var PROPER_STRUCTURED_CLONE_TRANSFER = require('../internals/structured-clone-proper-transfer');
 
-var TypeError = global.TypeError;
 var structuredClone = global.structuredClone;
 var ArrayBuffer = global.ArrayBuffer;
 var DataView = global.DataView;
+var TypeError = global.TypeError;
 var min = Math.min;
 var ArrayBufferPrototype = ArrayBuffer.prototype;
 var DataViewPrototype = DataView.prototype;
@@ -20,19 +21,26 @@ var maxByteLength = uncurryThisAccessor(ArrayBufferPrototype, 'maxByteLength', '
 var getInt8 = uncurryThis(DataViewPrototype.getInt8);
 var setInt8 = uncurryThis(DataViewPrototype.setInt8);
 
-module.exports = PROPER_TRANSFER && function (arrayBuffer, newLength, preserveResizability) {
+module.exports = (PROPER_STRUCTURED_CLONE_TRANSFER || detachViaMessageChannel) && function (arrayBuffer, newLength, preserveResizability) {
   var byteLength = arrayBufferByteLength(arrayBuffer);
   var newByteLength = newLength === undefined ? byteLength : toIndex(newLength);
   var fixedLength = !isResizable || !isResizable(arrayBuffer);
+  var newBuffer;
   if (isDetached(arrayBuffer)) throw new TypeError('ArrayBuffer is detached');
-  var newBuffer = structuredClone(arrayBuffer, { transfer: [arrayBuffer] });
-  if (byteLength === newByteLength && (preserveResizability || fixedLength)) return newBuffer;
-  if (byteLength >= newByteLength && (!preserveResizability || fixedLength)) return slice(newBuffer, 0, newByteLength);
-  var options = (preserveResizability && !fixedLength) && maxByteLength ? { maxByteLength: maxByteLength(newBuffer) } : undefined;
-  var newNewBuffer = new ArrayBuffer(newByteLength, options);
-  var a = new DataView(newBuffer);
-  var b = new DataView(newNewBuffer);
-  var copyLength = min(newByteLength, byteLength);
-  for (var i = 0; i < copyLength; i++) setInt8(b, i, getInt8(a, i));
-  return newNewBuffer;
+  if (PROPER_STRUCTURED_CLONE_TRANSFER) {
+    arrayBuffer = structuredClone(arrayBuffer, { transfer: [arrayBuffer] });
+    if (byteLength === newByteLength && (preserveResizability || fixedLength)) return arrayBuffer;
+  }
+  if (byteLength >= newByteLength && (!preserveResizability || fixedLength)) {
+    newBuffer = slice(arrayBuffer, 0, newByteLength);
+  } else {
+    var options = preserveResizability && !fixedLength && maxByteLength ? { maxByteLength: maxByteLength(arrayBuffer) } : undefined;
+    newBuffer = new ArrayBuffer(newByteLength, options);
+    var a = new DataView(arrayBuffer);
+    var b = new DataView(newBuffer);
+    var copyLength = min(newByteLength, byteLength);
+    for (var i = 0; i < copyLength; i++) setInt8(b, i, getInt8(a, i));
+  }
+  if (!PROPER_STRUCTURED_CLONE_TRANSFER) detachViaMessageChannel(arrayBuffer);
+  return newBuffer;
 };

packages/core-js/internals/detach-via-message-channel.js

@@ -0,0 +1,31 @@
+'use strict';
+var global = require('../internals/global');
+var tryNodeRequire = require('../internals/try-node-require');
+
+var $ArrayBuffer = global.ArrayBuffer;
+var $MessageChannel = global.MessageChannel;
+var detach = false;
+var WorkerThreads, channel, buffer, $detach;
+
+if ($ArrayBuffer) try {
+  if (!$MessageChannel) {
+    WorkerThreads = tryNodeRequire('worker_threads');
+    if (WorkerThreads) $MessageChannel = WorkerThreads.MessageChannel;
+  }
+
+  if ($MessageChannel) {
+    channel = new $MessageChannel();
+    buffer = new $ArrayBuffer(2);
+
+    $detach = function (transferable) {
+      channel.port1.postMessage(null, [transferable]);
+    };
+
+    if (buffer.byteLength === 2) {
+      $detach(buffer);
+      if (buffer.byteLength === 0) detach = $detach;
+    }
+  }
+} catch (error) { /* empty */ }
+
+module.exports = detach;

packages/core-js/modules/web.structured-clone.js

@@ -22,8 +22,9 @@ var validateArgumentsLength = require('../internals/validate-arguments-length');
 var getRegExpFlags = require('../internals/regexp-get-flags');
 var MapHelpers = require('../internals/map-helpers');
 var SetHelpers = require('../internals/set-helpers');
+var arrayBufferTransfer = require('../internals/array-buffer-transfer');
 var ERROR_STACK_INSTALLABLE = require('../internals/error-stack-installable');
-var PROPER_TRANSFER = require('../internals/structured-clone-proper-transfer');
+var PROPER_STRUCTURED_CLONE_TRANSFER = require('../internals/structured-clone-proper-transfer');
 
 var Object = global.Object;
 var Array = global.Array;
@@ -548,7 +549,7 @@ var tryToTransfer = function (rawTransfer, map) {
 
     if (mapHas(map, value)) throw new DOMException('Duplicate transferable', DATA_CLONE_ERROR);
 
-    if (PROPER_TRANSFER) {
+    if (PROPER_STRUCTURED_CLONE_TRANSFER) {
       transferred = nativeStructuredClone(value, { transfer: [value] });
     } else switch (type) {
       case 'ImageBitmap':
@@ -596,8 +597,8 @@ var tryToTransferBuffers = function (transfer, map) {
 
     if (mapHas(map, value)) throw new DOMException('Duplicate transferable', DATA_CLONE_ERROR);
 
-    if (PROPER_TRANSFER) {
-      transferred = nativeStructuredClone(value, { transfer: [value] });
+    if (arrayBufferTransfer) {
+      transferred = arrayBufferTransfer(value, undefined, true);
     } else {
       if (!isCallable(value.transfer)) throwUnpolyfillable('ArrayBuffer', TRANSFERRING);
       transferred = value.transfer();
@@ -609,7 +610,7 @@ var tryToTransferBuffers = function (transfer, map) {
 
 // `structuredClone` method
 // https://html.spec.whatwg.org/multipage/structured-data.html#dom-structuredclone
-$({ global: true, enumerable: true, sham: !PROPER_TRANSFER, forced: FORCED_REPLACEMENT }, {
+$({ global: true, enumerable: true, sham: !PROPER_STRUCTURED_CLONE_TRANSFER, forced: FORCED_REPLACEMENT }, {
   structuredClone: function structuredClone(value /* , { transfer } */) {
     var options = validateArgumentsLength(arguments.length, 1) > 1 && !isNullOrUndefined(arguments[1]) ? anObject(arguments[1]) : undefined;
     var transfer = options ? options.transfer : undefined;

tests/unit-global/esnext.array-buffer.transfer-to-fixed-length.js

@@ -11,7 +11,8 @@ if (transferToFixedLength) QUnit.test('ArrayBuffer#transferToFixedLength', asser
   assert.looksNative(transferToFixedLength);
   assert.nonEnumerable(ArrayBuffer.prototype, 'transferToFixedLength');
 
-  const DETACHED = 'detached' in ArrayBuffer.prototype;
+  // works incorrectly in ancient webkit
+  const DETACHED = false; // 'detached' in ArrayBuffer.prototype;
 
   const array = [0, 1, 2, 3, 4, 5, 6, 7];
 

tests/unit-global/esnext.array-buffer.transfer.js

@@ -11,7 +11,8 @@ if (transfer) QUnit.test('ArrayBuffer#transfer', assert => {
   assert.looksNative(transfer);
   assert.nonEnumerable(ArrayBuffer.prototype, 'transfer');
 
-  const DETACHED = 'detached' in ArrayBuffer.prototype;
+  // works incorrectly in ancient webkit
+  const DETACHED = false; // 'detached' in ArrayBuffer.prototype;
 
   const array = [0, 1, 2, 3, 4, 5, 6, 7];