Implement .forEach() on typed arrays

test/mjsunit/harmony/typedarrays-foreach.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-typedarrays
+
+var typedArrayConstructors = [
+  Uint8Array,
+  Int8Array,
+  Uint16Array,
+  Int16Array,
+  Uint32Array,
+  Int32Array,
+  Uint8ClampedArray,
+  Float32Array,
+  Float64Array];
+
+function TestTypedArrayForEach(constructor) {
+  assertEquals(1, constructor.prototype.forEach.length);
+
+  var a = new constructor(2);
+  a[0] = 0;
+  a[1] = 1;
+
+  var count = 0;
+  a.forEach(function (n) { count++; });
+  assertEquals(2, count);
+
+  // Use specified object as this object when calling the function.
+  var o = { value: 42 };
+  var result = [];
+  a.forEach(function (n, index, array) { result.push(this.value); }, o);
+  assertArrayEquals([42, 42], result);
+
+  // Modify the original array.
+  count = 0;
+  a.forEach(function (n, index, array) { array[index] = n + 1; count++ });
+  assertEquals(2, count);
+  assertArrayEquals([1, 2], a);
+

[Dmitry Lomov (no reviews), 2014/10/08 13:57:11]

Add test for a function that throws exception midway.

Add a test that neuters a typed array midway (use %ArrayBufferNeuter).

Add a test with externalizes typed array midway (calls .buffer)
Add a test that constructs typed array using %TypedArray(ArrayBuffer)
constructor. 

+  // The %TypedArray%.forEach() method should not work when
+  // transplanted to objects that are not typed arrays.
+  a = [1, 2, 3];
+  a.forEach = constructor.prototype.forEach;
+  assertThrows(function () { a.forEach(function (x) {}) }, TypeError);

[Dmitry Lomov (no reviews), 2014/10/08 13:57:11]

Also test for non-array (e.g. {}). 

Use constructor.prototype.forEach.call.

Also test for primitives (1, "abc")

+}
+
+for (i = 0; i < typedArrayConstructors.length; i++) {
+  TestTypedArrayForEach(typedArrayConstructors[i]);
+}
+
+// Transplanting the method from one typed array to another
+// typed array should work normally.
+var a = new Int8Array(4);
+a.forEach = Uint32Array.prototype.forEach;

[Dmitry Lomov (no reviews), 2014/10/08 13:57:11]

Use Uint32Array.prototype.forEach.call - more straightforward.
Also, ensure that you execute all combinations (using typedArrayConstructors
array)

+var count = 0;
+a.forEach(function (x) { count++ });
+assertEquals(a.length, count);