Array.prototype.{every, filter, find, findIndex, forEach, map, some}: Use fresh primitive wrapper f…

src/harmony-array.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.
 
 'use strict';
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
 // -------------------------------------------------------------------
 
 // ES6 draft 07-15-13, section 15.4.3.23
-function ArrayFind(predicate /* thisArg */) {  // length == 1
+function ArrayFind(predicate /* receiver */) {  // length == 1

[wingo, 2014/09/23 18:39:01]

So in the last patch I wanted to avoid new_thisArg (mixed underscores and
camelcase).  I suggested a fix to replace new_thisArg by receiver, though
perhaps it was unclear.  Now in this patch you changed the thisArg name to
receiver, which probably isn't the right thing, as the spec calls it thisArg. 
Please change it back; the only thing that really needs renaming was your
new_thisArg.  You could call it receiver or newThisArg or anything that keeps
the style :)

[Diego Pino, 2014/09/24 10:13:01]

OK, understood.

It's worth noticing that array functions 'filter', 'forEach', 'map', 'same' and
'every', call this parameter 'receiver' although the spec also names it
'thisArg'. Maybe at some point is worth to do a refactoring and use the same
name for all functions. For the moment I agree with not changing the name of
this parameter.

   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.find");
 
   var array = ToObject(this);
   var length = ToInteger(array.length);
 
   if (!IS_SPEC_FUNCTION(predicate)) {
     throw MakeTypeError('called_non_callable', [predicate]);
   }
 
-  var thisArg;
+  var receiver;
   if (%_ArgumentsLength() > 1) {
-    thisArg = %_Arguments(1);
+    receiver = %_Arguments(1);
   }
 
-  if (IS_NULL_OR_UNDEFINED(thisArg)) {
-    thisArg = %GetDefaultReceiver(predicate) || thisArg;
-  } else if (!IS_SPEC_OBJECT(thisArg) && %IsSloppyModeFunction(predicate)) {
-    thisArg = ToObject(thisArg);
+  if (IS_NULL_OR_UNDEFINED(receiver)) {
+    receiver = %GetDefaultReceiver(predicate) || receiver;
   }
+  var needs_wrapper = SHOULD_CREATE_WRAPPER(predicate, receiver);
 
   for (var i = 0; i < length; i++) {
     if (i in array) {
       var element = array[i];
-      if (%_CallFunction(thisArg, element, i, array, predicate)) {
+      var new_receiver = needs_wrapper ? ToObject(receiver) : receiver;
+      if (%_CallFunction(new_receiver, element, i, array, predicate)) {
         return element;
       }
     }
   }
 
   return;
 }
 
 
 // ES6 draft 07-15-13, section 15.4.3.24
-function ArrayFindIndex(predicate /* thisArg */) {  // length == 1
+function ArrayFindIndex(predicate /* receiver */) {  // length == 1
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.findIndex");
 
   var array = ToObject(this);
   var length = ToInteger(array.length);
 
   if (!IS_SPEC_FUNCTION(predicate)) {
     throw MakeTypeError('called_non_callable', [predicate]);
   }
 
-  var thisArg;
+  var receiver;
   if (%_ArgumentsLength() > 1) {
-    thisArg = %_Arguments(1);
+    receiver = %_Arguments(1);
   }
 
-  if (IS_NULL_OR_UNDEFINED(thisArg)) {
-    thisArg = %GetDefaultReceiver(predicate) || thisArg;
-  } else if (!IS_SPEC_OBJECT(thisArg) && %IsSloppyModeFunction(predicate)) {
-    thisArg = ToObject(thisArg);
+  if (IS_NULL_OR_UNDEFINED(receiver)) {
+    receiver = %GetDefaultReceiver(predicate) || receiver;
   }
+  var needs_wrapper = SHOULD_CREATE_WRAPPER(predicate, receiver);
 
   for (var i = 0; i < length; i++) {
     if (i in array) {
       var element = array[i];
-      if (%_CallFunction(thisArg, element, i, array, predicate)) {
+      var new_receiver = needs_wrapper ? ToObject(receiver) : receiver;
+      if (%_CallFunction(new_receiver, element, i, array, predicate)) {
         return i;
       }
     }
   }
 
   return -1;
 }
 
 
 // ES6, draft 04-05-14, section 22.1.3.6
@@ skipping 64 matching lines @@
 
   // Set up the non-enumerable functions on the Array prototype object.
   InstallFunctions($Array.prototype, DONT_ENUM, $Array(
     "find", ArrayFind,
     "findIndex", ArrayFindIndex,
     "fill", ArrayFill
   ));
 }
 
 HarmonyArrayExtendArrayPrototype();