Implement .every() on typed arrays

test/mjsunit/harmony/typedarrays-every.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-arrays --allow-natives-syntax
 
+// The tests here are essentially the same as the ones for
+// %TypedArray%.prototype.forEach, modified to take into account
+// that callbacks must return a boolean value, plus an extra test
+// to check whether returning "false" stops iteration.
+
 var typedArrayConstructors = [
   Uint8Array,
   Int8Array,
   Uint16Array,
   Int16Array,
   Uint32Array,
   Int32Array,
   Uint8ClampedArray,
   Float32Array,
   Float64Array];
 
 function CheckTypedArrayIsNeutered(array) {
   assertEquals(0, array.byteLength);
   assertEquals(0, array.byteOffset);
   assertEquals(0, array.length);
 }
 
-function TestTypedArrayForEach(constructor) {
-  assertEquals(1, constructor.prototype.forEach.length);
+function TestTypedArrayEvery(constructor) {
+  assertEquals(1, constructor.prototype.every.length);
 
   var a = new constructor(2);
   a[0] = 0;
   a[1] = 1;
 
   var count = 0;
-  a.forEach(function (n) { count++; });
+  a.every(function (n) { count++; return true; });
   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);
+  a.every(function (n, index, array) { result.push(this.value); return true; }, o);
   assertArrayEquals([42, 42], result);
 
   // Modify the original array.
   count = 0;
-  a.forEach(function (n, index, array) { array[index] = n + 1; count++ });
+  a.every(function (n, index, array) { array[index] = n + 1; count++; return true; });
   assertEquals(2, count);
   assertArrayEquals([1, 2], a);
 
+  // Returning "false" stops the iteration.
+  count = 0;
+  a.every(function (n, index, array) { array[index] = 42; count++; return false; });
+  assertEquals(1, count);
+  assertArrayEquals([42, 2], a);
+
   // Check that values passed as second argument are wrapped into
   // objects when calling into sloppy mode functions.
   function CheckWrapping(value, wrapper) {
     var wrappedValue = new wrapper(value);
 
-    a.forEach(function () {
+    a.every(function () {
       assertEquals("object", typeof this);
       assertEquals(wrappedValue, this);
+      return true;
     }, value);
 
-    a.forEach(function () {
+    a.every(function () {
       "use strict";
       assertEquals(typeof value, typeof this);
       assertEquals(value, this);
+      return true;
     }, value);
   }
   CheckWrapping(true, Boolean);
   CheckWrapping(false, Boolean);
   CheckWrapping("xxx", String);
   CheckWrapping(42, Number);
   CheckWrapping(3.14, Number);
   CheckWrapping({}, Object);
 
   // Throw before completing iteration, only the first element
   // should be modified when thorwing mid-way.
   count = 0;
   a[0] = 42;
   a[1] = 42;
   try {
-    a.forEach(function (n, index, array) {
+    a.every(function (n, index, array) {
       if (count > 0) throw "meh";
       array[index] = n + 1;
       count++;
+      return true;
     });
   } catch (e) {
   }
   assertEquals(1, count);
   assertEquals(43, a[0]);
   assertEquals(42, a[1]);
 
   // Neutering the buffer backing the typed array mid-way should
-  // still make .forEach() finish, and the array should keep being
+  // still make .every() finish, and the array should keep being
   // empty after neutering it.
   count = 0;
-  a.forEach(function (n, index, array) {
+  a.every(function (n, index, array) {
     if (count > 0) %ArrayBufferNeuter(array.buffer);
     array[index] = n + 1;
     count++;
+    return true;
   });
   assertEquals(2, count);
   CheckTypedArrayIsNeutered(a);
   assertEquals(undefined, a[0]);
 
   // The method must work for typed arrays created from ArrayBuffer.
   // The length of the ArrayBuffer is chosen so it is a multiple of
   // all lengths of the typed array items.
   a = new constructor(new ArrayBuffer(64));
   count = 0;
-  a.forEach(function (n) { count++ });
+  a.every(function (n) { count++; return true; });
   assertEquals(a.length, count);
 
   // Externalizing the array mid-way accessing the .buffer property
   // should work.
   a = new constructor(2);
   count = 0;
   var buffer = undefined;
-  a.forEach(function (n, index, array) {
+  a.every(function (n, index, array) {
     if (count++ > 0)
       buffer = array.buffer;
+    return true;
   });
   assertEquals(2, count);
   assertTrue(!!buffer);
   assertEquals("ArrayBuffer", %_ClassOf(buffer));
   assertSame(buffer, a.buffer);
 
-  // The %TypedArray%.forEach() method should not work when
+  // The %TypedArray%.every() method should not work when
   // transplanted to objects that are not typed arrays.
-  assertThrows(function () { constructor.prototype.forEach.call([1, 2, 3], function (x) {}) }, TypeError);
-  assertThrows(function () { constructor.prototype.forEach.call("abc", function (x) {}) }, TypeError);
-  assertThrows(function () { constructor.prototype.forEach.call({}, function (x) {}) }, TypeError);
-  assertThrows(function () { constructor.prototype.forEach.call(0, function (x) {}) }, TypeError);
+  assertThrows(function () { constructor.prototype.every.call([1, 2, 3], function (x) {}) }, TypeError);
+  assertThrows(function () { constructor.prototype.every.call("abc", function (x) {}) }, TypeError);
+  assertThrows(function () { constructor.prototype.every.call({}, function (x) {}) }, TypeError);
+  assertThrows(function () { constructor.prototype.every.call(0, function (x) {}) }, TypeError);
 
   // Method must be useable on instances of other typed arrays.
-  for (var i = 0; i < typedArrayConstructors.length; i++) {
+  for (var otherConstructor of typedArrayConstructors) {
     count = 0;
-    a = new typedArrayConstructors[i](4);
-    constructor.prototype.forEach.call(a, function (x) { count++ });
+    a = new otherConstructor(4);
+    constructor.prototype.every.call(a, function (x) { count++; return true; });
     assertEquals(a.length, count);
   }
 }
 
-for (i = 0; i < typedArrayConstructors.length; i++) {
-  TestTypedArrayForEach(typedArrayConstructors[i]);
+for (var constructor of typedArrayConstructors) {
+  TestTypedArrayEvery(constructor);
 }