Implement %TypedArray%.prototype.{map,filter,some,reduce,reduceRight}

src/harmony-typedarray.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.
 
 (function(global, exports) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 12 matching lines @@
 
 macro DECLARE_GLOBALS(NAME)
 var GlobalNAME = global.NAME;
 endmacro
 
 TYPED_ARRAYS(DECLARE_GLOBALS)
 DECLARE_GLOBALS(Array)
 
 // -------------------------------------------------------------------
 
+function ConstructTypedArray(constructor, array) {
+  // TODO(littledan): This is an approximation of the spec, which requires
+  // that only real TypedArray classes should be accepted (22.2.2.1.1)
+  if (!IS_SPEC_OBJECT(constructor) || IS_UNDEFINED(constructor.prototype) ||
+      !%HasOwnProperty(constructor.prototype, "BYTES_PER_ELEMENT")) {
+    throw MakeTypeError(kNotTypedArray);
+  }
+
+  // TODO(littledan): The spec requires that, rather than directly calling
+  // the constructor, a TypedArray is created with the proper proto and
+  // underlying size and element size, and elements are put in one by one.
+  // By contrast, this would allow subclasses to make a radically different
+  // constructor with different semantics.
+  return new constructor(array);
+}
+
+function ConstructTypedArrayLike(typedArray, arrayContents) {
+  // TODO(littledan): The spec requires that we actuallly use
+  // typedArray.constructor[Symbol.species] (bug v8:4093)
+  return new typedArray.constructor(arrayContents);
+}
+
 function TypedArrayCopyWithin(target, start, end) {
   if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
 
   var length = %_TypedArrayGetLength(this);
 
   // TODO(littledan): Replace with a memcpy for better performance
   return $innerArrayCopyWithin(target, start, end, this, length);
 }
 %FunctionSetLength(TypedArrayCopyWithin, 2);
 
@@ skipping 11 matching lines @@
 function TypedArrayForEach(f, receiver) {
   if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
 
   var length = %_TypedArrayGetLength(this);
 
   $innerArrayForEach(f, receiver, this, length);
 }
 %FunctionSetLength(TypedArrayForEach, 1);
 
 // ES6 draft 04-05-14 section 22.2.3.8
-function TypedArrayFill(value, start , end) {
+function TypedArrayFill(value, start, end) {
   if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
 
   var length = %_TypedArrayGetLength(this);
 
   return $innerArrayFill(value, start, end, this, length);
 }
 %FunctionSetLength(TypedArrayFill, 1);
 
+// ES6 draft 07-15-13, section 22.2.3.9
+function TypedArrayFilter(predicate, thisArg) {
+  if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
+
+  var length = %_TypedArrayGetLength(this);
+  var array = $innerArrayFilter(predicate, thisArg, this, length);
+  return ConstructTypedArrayLike(this, array);
+}
+%FunctionSetLength(TypedArrayFilter, 1);
+
 // ES6 draft 07-15-13, section 22.2.3.10
 function TypedArrayFind(predicate, thisArg) {
   if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
 
   var length = %_TypedArrayGetLength(this);
 
   return $innerArrayFind(predicate, thisArg, this, length);
 }
 %FunctionSetLength(TypedArrayFind, 1);
 
 // ES6 draft 07-15-13, section 22.2.3.11
 function TypedArrayFindIndex(predicate, thisArg) {
   if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
 
   var length = %_TypedArrayGetLength(this);
 
   return $innerArrayFindIndex(predicate, thisArg, this, length);
 }
 %FunctionSetLength(TypedArrayFindIndex, 1);
 
 
+// ES6 draft 07-15-13, section 22.2.3.18
+function TypedArrayMap(predicate, thisArg) {
+  if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
+
+  // TODO(littledan): Preallocate rather than making an intermediate
+  // array, for better performance.
+  var length = %_TypedArrayGetLength(this);
+  var array = $innerArrayMap(predicate, thisArg, this, length);
+  return ConstructTypedArrayLike(this, array);
+}
+%FunctionSetLength(TypedArrayMap, 1);
+
+
+// ES6 draft 07-15-13, section 22.2.3.19
+function TypedArrayReduce(callback, current) {
+  if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
+
+  var length = %_TypedArrayGetLength(this);
+  return $innerArrayReduce(callback, current, this, length,
+                           %_ArgumentsLength());
+}
+%FunctionSetLength(TypedArrayReduce, 1);
+
+
+// ES6 draft 07-15-13, section 22.2.3.19
+function TypedArrayReduceRight(callback, current) {
+  if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
+
+  var length = %_TypedArrayGetLength(this);
+  return $innerArrayReduceRight(callback, current, this, length,
+                                %_ArgumentsLength());
+}
+%FunctionSetLength(TypedArrayReduceRight, 1);
+
+
+// ES6 draft 05-05-15, section 22.2.3.24
+function TypedArraySome(f, receiver) {
+  if (!%IsTypedArray(this)) throw MakeTypeError(kNotTypedArray);
+
+  var length = %_TypedArrayGetLength(this);
+
+  return $innerArraySome(f, receiver, this, length);
+}
+%FunctionSetLength(TypedArraySome, 1);
+
+
 // ES6 draft 08-24-14, section 22.2.2.2
 function TypedArrayOf() {
   var length = %_ArgumentsLength();
   var array = new this(length);
   for (var i = 0; i < length; i++) {
     array[i] = %_Arguments(i);
   }
   return array;
 }
 
@@ skipping 26 matching lines @@
   // Set up non-enumerable functions on the object.
   $installFunctions(GlobalNAME, DONT_ENUM | DONT_DELETE | READ_ONLY, [
     "from", TypedArrayFrom,
     "of", TypedArrayOf
   ]);
 
   // Set up non-enumerable functions on the prototype object.
   $installFunctions(GlobalNAME.prototype, DONT_ENUM, [
     "copyWithin", TypedArrayCopyWithin,
     "every", TypedArrayEvery,
-    "forEach", TypedArrayForEach,
+    "fill", TypedArrayFill,
+    "filter", TypedArrayFilter,
     "find", TypedArrayFind,
     "findIndex", TypedArrayFindIndex,
-    "fill", TypedArrayFill
+    "forEach", TypedArrayForEach,
+    "map", TypedArrayMap,
+    "reduce", TypedArrayReduce,
+    "reduceRight", TypedArrayReduceRight,
+    "some", TypedArraySome
   ]);
 endmacro
 
 TYPED_ARRAYS(EXTEND_TYPED_ARRAY)
 
 })