[es6] don't throw if argument is non-object (O.freeze, O.seal, O.preventExtensions)

src/v8natives.js

 // Copyright 2012 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.
 
 // This file relies on the fact that the following declarations have been made
 // in runtime.js:
 // var $Object = global.Object;
 // var $Boolean = global.Boolean;
 // var $Number = global.Number;
 // var $Function = global.Function;
@@ skipping 1223 matching lines @@
     obj.length = 0;
   } else {
     %Fix(obj);
   }
   ObjectDefineProperties(obj, props);
 }
 
 
 // ES5 section 15.2.3.8.
 function ObjectSealJS(obj) {
-  if (!IS_SPEC_OBJECT(obj)) {
-    throw MakeTypeError("called_on_non_object", ["Object.seal"]);
-  }
+  if (!IS_SPEC_OBJECT(obj)) return obj;
   var isProxy = %_IsJSProxy(obj);
   if (isProxy || %HasSloppyArgumentsElements(obj) || %IsObserved(obj)) {
     if (isProxy) {
       ProxyFix(obj);
     }
     var names = ObjectGetOwnPropertyNames(obj);
     for (var i = 0; i < names.length; i++) {
       var name = names[i];
       var desc = GetOwnPropertyJS(obj, name);
       if (desc.isConfigurable()) {
         desc.setConfigurable(false);
         DefineOwnProperty(obj, name, desc, true);
       }
     }
     %PreventExtensions(obj);
   } else {
     // TODO(adamk): Is it worth going to this fast path if the
     // object's properties are already in dictionary mode?
     %ObjectSeal(obj);
   }
   return obj;
 }
 
 
 // ES5 section 15.2.3.9.
 function ObjectFreezeJS(obj) {
-  if (!IS_SPEC_OBJECT(obj)) {
-    throw MakeTypeError("called_on_non_object", ["Object.freeze"]);
-  }
+  if (!IS_SPEC_OBJECT(obj)) return obj;
   var isProxy = %_IsJSProxy(obj);
   if (isProxy || %HasSloppyArgumentsElements(obj) || %IsObserved(obj)) {
     if (isProxy) {
       ProxyFix(obj);
     }
     var names = ObjectGetOwnPropertyNames(obj);
     for (var i = 0; i < names.length; i++) {
       var name = names[i];
       var desc = GetOwnPropertyJS(obj, name);
       if (desc.isWritable() || desc.isConfigurable()) {
         if (IsDataDescriptor(desc)) desc.setWritable(false);
         desc.setConfigurable(false);
         DefineOwnProperty(obj, name, desc, true);
       }
     }
     %PreventExtensions(obj);
   } else {
     // TODO(adamk): Is it worth going to this fast path if the
     // object's properties are already in dictionary mode?
     %ObjectFreeze(obj);
   }
   return obj;
 }
 
 
 // ES5 section 15.2.3.10
 function ObjectPreventExtension(obj) {
-  if (!IS_SPEC_OBJECT(obj)) {
-    throw MakeTypeError("called_on_non_object", ["Object.preventExtension"]);
-  }
+  if (!IS_SPEC_OBJECT(obj)) return obj;
   if (%_IsJSProxy(obj)) {
     ProxyFix(obj);
   }
   %PreventExtensions(obj);
   return obj;
 }
 
 
 // ES5 section 15.2.3.11
 function ObjectIsSealed(obj) {
-  if (!IS_SPEC_OBJECT(obj)) {
-    throw MakeTypeError("called_on_non_object", ["Object.isSealed"]);
-  }
+  if (!IS_SPEC_OBJECT(obj)) return true;
   if (%_IsJSProxy(obj)) {
     return false;
   }
   if (%IsExtensible(obj)) {
     return false;
   }
   var names = ObjectGetOwnPropertyNames(obj);
   for (var i = 0; i < names.length; i++) {
     var name = names[i];
     var desc = GetOwnPropertyJS(obj, name);
     if (desc.isConfigurable()) {
       return false;
     }
   }
   return true;
 }
 
 
 // ES5 section 15.2.3.12
 function ObjectIsFrozen(obj) {
-  if (!IS_SPEC_OBJECT(obj)) {
-    throw MakeTypeError("called_on_non_object", ["Object.isFrozen"]);
-  }
+  if (!IS_SPEC_OBJECT(obj)) return true;
   if (%_IsJSProxy(obj)) {
     return false;
   }
   if (%IsExtensible(obj)) {
     return false;
   }
   var names = ObjectGetOwnPropertyNames(obj);
   for (var i = 0; i < names.length; i++) {
     var name = names[i];
     var desc = GetOwnPropertyJS(obj, name);
     if (IsDataDescriptor(desc) && desc.isWritable()) return false;
     if (desc.isConfigurable()) return false;
   }
   return true;
 }
 
 
 // ES5 section 15.2.3.13
 function ObjectIsExtensible(obj) {
-  if (!IS_SPEC_OBJECT(obj)) {
-    throw MakeTypeError("called_on_non_object", ["Object.isExtensible"]);
-  }
+  if (!IS_SPEC_OBJECT(obj)) return false;
   if (%_IsJSProxy(obj)) {
     return true;
   }
   return %IsExtensible(obj);
 }
 
 
 // ECMA-262, Edition 6, section 19.1.2.10
 function ObjectIs(obj1, obj2) {
   return SameValue(obj1, obj2);
@@ skipping 520 matching lines @@
   }
   if (!IS_SPEC_FUNCTION(method)) {
     throw MakeTypeError('not_iterable', [obj]);
   }
   var iterator = %_CallFunction(obj, method);
   if (!IS_SPEC_OBJECT(iterator)) {
     throw MakeTypeError('not_an_iterator', [iterator]);
   }
   return iterator;
 }