The Property Descriptor Specification Type
- The Property Descriptor type is used to explain the manipulation and reification of Object property attributes. Values of the Property Descriptor type are Records. Each field's name is an attribute name and its value is a corresponding attribute value as specified in . In addition, any field may be present or absent. The schema name used within this specification to tag literal descriptions of Property Descriptor records is “PropertyDescriptor”.
+ The Property Descriptor type is used to explain the manipulation and reification of Object property attributes. A Property Descriptor is a Record with zero or more fields, where each field's name is an attribute name and its value is a corresponding attribute value as specified in . The schema name used within this specification to tag literal descriptions of Property Descriptor records is “PropertyDescriptor”.
Property Descriptor values may be further classified as data Property Descriptors and accessor Property Descriptors based upon the existence or use of certain fields. A data Property Descriptor is one that includes any fields named either [[Value]] or [[Writable]]. An accessor Property Descriptor is one that includes any fields named either [[Get]] or [[Set]]. Any Property Descriptor may have fields named [[Enumerable]] and [[Configurable]]. A Property Descriptor value may not be both a data Property Descriptor and an accessor Property Descriptor; however, it may be neither (in which case it is a generic Property Descriptor). A fully populated Property Descriptor is one that is either an accessor Property Descriptor or a data Property Descriptor and that has all of the corresponding fields defined in .
The following abstract operations are used in this specification to operate upon Property Descriptor values:
@@ -12626,7 +12626,7 @@
1. Create an own data property named _P_ of object _O_ whose [[Value]], [[Writable]], [[Enumerable]], and [[Configurable]] attributes are set to the value of the corresponding field in _Desc_ if _Desc_ has that field, or to the attribute's default value otherwise.
1. Return *true*.
1. Assert: _current_ is a fully populated Property Descriptor.
- 1. If every field in _Desc_ is absent, return *true*.
+ 1. If _Desc_ does not have any fields, return *true*.
1. If _current_.[[Configurable]] is *false*, then
1. If _Desc_ has a [[Configurable]] field and _Desc_.[[Configurable]] is *true*, return *false*.
1. If _Desc_ has an [[Enumerable]] field and ! SameValue(_Desc_.[[Enumerable]], _current_.[[Enumerable]]) is *false*, return *false*.
@@ -12647,7 +12647,7 @@
1. If _Desc_ has a [[Enumerable]] field, let _enumerable_ be _Desc_.[[Enumerable]]; else let _enumerable_ be _current_.[[Enumerable]].
1. Replace the property named _P_ of object _O_ with a data property whose [[Configurable]] and [[Enumerable]] attributes are set to _configurable_ and _enumerable_, respectively, and whose [[Value]] and [[Writable]] attributes are set to the value of the corresponding field in _Desc_ if _Desc_ has that field, or to the attribute's default value otherwise.
1. Else,
- 1. For each field of _Desc_ that is present, set the corresponding attribute of the property named _P_ of object _O_ to the value of the field.
+ 1. For each field of _Desc_, set the corresponding attribute of the property named _P_ of object _O_ to the value of the field.
1. Return *true*.