Reflect.defineProperty + FromPropertyDescriptor & ToPropertyDescriptor

Michael Dyck jmdyck at
Tue Sep 4 17:25:06 UTC 2018

On 2018-09-04 12:02 PM, Allen Wirfs-Brock wrote:
> At one point, early in the development of ES6 the draft spec. had a 
> [[OriginalDescriptor]] field  (that may not be the actual name I used) in 
> internal PropertyDescrptors that carried along a reference to the original 
> descriptor object from which the PropertyDescriptor was derived.

It looks like you're talking about [[Origin]].

Working drafts 12 though 25 had this wording or similar:
   A Property Descriptor may be derived from an object that has properties
   that directly correspond to the fields of a Property Descriptor. Such a
   derived Property Descriptor has an additional field named [[Origin]]
   whose value is the object from which the Property Descriptor was derived.

(In case that helps anyone researching this.)


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