[typedarrays] Implement %TypedArray%.prototype.lastIndexOf in C++

src/js/typedarray.js

 // Copyright 2013 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, utils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 496 matching lines @@
   var length = %_TypedArrayGetLength(this);
 
   if (IS_UNDEFINED(comparefn)) {
     return %TypedArraySortFast(this);
   }
 
   return InnerArraySort(this, length, comparefn);
 }
 
 
-// ES6 section 22.2.3.16
-function TypedArrayLastIndexOf(element, index) {
-  if (!IS_TYPEDARRAY(this)) throw %make_type_error(kNotTypedArray);
-
-  var length = %_TypedArrayGetLength(this);
-
-  if (length === 0) return -1;
-  if (!IS_NUMBER(element)) return -1;
-  var n;
-  if (arguments.length < 2) {
-    n = length - 1;
-  } else {
-    n = TO_INTEGER(index);
-  }
-
-  var k;
-  if (n >= 0) {
-    if (length <= n) {
-      k = length - 1;
-    } else if (n === 0) {
-      k = 0;
-    } else {
-      k = n;
-    }
-  } else {
-    k = length + n;
-  }
-
-  while (k >= 0) {
-    var elementK = this[k];
-    if (element === elementK) {
-      return k;
-    }
-    --k;
-  }
-  return -1;
-}
-%FunctionSetLength(TypedArrayLastIndexOf, 1);
-
-
 // ES6 draft 07-15-13, section 22.2.3.18
 function TypedArrayMap(f, thisArg) {
   if (!IS_TYPEDARRAY(this)) throw %make_type_error(kNotTypedArray);
 
   var length = %_TypedArrayGetLength(this);
   var result = TypedArraySpeciesCreate(this, length);
   if (!IS_CALLABLE(f)) throw %make_type_error(kCalledNonCallable, f);
   for (var i = 0; i < length; i++) {
     var element = this[i];
     result[i] = %_Call(f, thisArg, element, i, this);
@@ skipping 173 matching lines @@
                     TypedArrayGetToStringTag);
 utils.InstallFunctions(GlobalTypedArray.prototype, DONT_ENUM, [
   "subarray", TypedArraySubArray,
   "set", TypedArraySet,
   "every", TypedArrayEvery,
   "fill", TypedArrayFill,
   "filter", TypedArrayFilter,
   "find", TypedArrayFind,
   "findIndex", TypedArrayFindIndex,
   "join", TypedArrayJoin,
-  "lastIndexOf", TypedArrayLastIndexOf,
   "forEach", TypedArrayForEach,
   "map", TypedArrayMap,
   "reduce", TypedArrayReduce,
   "reduceRight", TypedArrayReduceRight,
   "reverse", TypedArrayReverse,
   "slice", TypedArraySlice,
   "some", TypedArraySome,
   "sort", TypedArraySort,
   "toLocaleString", TypedArrayToLocaleString
 ]);
@@ skipping 14 matching lines @@
   %AddNamedProperty(GlobalNAME.prototype,
                     "constructor", global.NAME, DONT_ENUM);
   %AddNamedProperty(GlobalNAME.prototype,
                     "BYTES_PER_ELEMENT", ELEMENT_SIZE,
                     READ_ONLY | DONT_ENUM | DONT_DELETE);
 endmacro
 
 TYPED_ARRAYS(SETUP_TYPED_ARRAY)
 
 })