[MERGE #5742 @Dachande663] Fixed #5621 - toLocaleString now accesses object property

Merge pull request #5742 from Dachande663:pr/dachande663/fix-tolocalestring-object-property

As per issue #5621, this PR enables toLocaleString to call JavascriptString underlying property.

Author: sethbrenith

lib/Runtime/Language/JavascriptConversion.cpp

@@ -701,9 +701,6 @@ using namespace Js;
         case TypeIds_Number:
             return JavascriptNumber::ToLocaleString(JavascriptNumber::GetValue(aValue), scriptContext);
 
-        case TypeIds_String:
-            return UnsafeVarTo<JavascriptString>(aValue);
-
         case TypeIds_VariantDate:
             // Legacy behavior was to create an empty object and call toLocaleString on it, which would result in this value
             return scriptContext->GetLibrary()->GetObjectDisplayString();

test/Array/toLocaleString.baseline

@@ -43,3 +43,15 @@ TypeError : The value of the property 'toLocaleString' is not a Function object
 
 9. Array: toLocaleString should use length property
 10.00, 20.00, 30.00, , , 
+
+
+10. Array: toLocaleString should use toLocaleString accessor on element
+accessor-value
+
+
+11. Array: toLocaleString should throw TypeError on undefined
+TypeError : The value of the property 'toLocaleString' is not a Function object
+
+
+12. Array: toLocaleString should throw TypeError on invalid function
+TypeError : The value of the property 'toLocaleString' is not a Function object

test/Array/toLocaleString.js

@@ -184,3 +184,32 @@ guarded_call(function () {
         echo(output);
     }
 });
+
+scenario("Array: toLocaleString should use toLocaleString accessor on element");
+var originalToLocaleString = String.prototype.toLocaleString;
+String.prototype.toLocaleString = function () {
+    return "accessor-value";
+};
+var o = ["test"];
+guarded_call(function () {
+    echo(Array.prototype.toLocaleString.apply(o));
+});
+String.prototype.toLocaleString = originalToLocaleString;
+
+scenario("Array: toLocaleString should throw TypeError on undefined");
+var originalToLocaleString = String.prototype.toLocaleString;
+String.prototype.toLocaleString = undefined;
+var o = ["test"];
+guarded_call(function () {
+    echo(Array.prototype.toLocaleString.apply(o));
+});
+String.prototype.toLocaleString = originalToLocaleString;
+
+scenario("Array: toLocaleString should throw TypeError on invalid function");
+var originalToLocaleString = String.prototype.toLocaleString;
+String.prototype.toLocaleString = 0;
+var o = ["test"];
+guarded_call(function () {
+    echo(Array.prototype.toLocaleString.apply(o));
+});
+String.prototype.toLocaleString = originalToLocaleString;