I didn't get a direct response to my question about mutating proto on objects which don't inherit from Object.prototype, but I'm inferring from [1] that it won't be possible. I find this unfortunate, but I realize this issue has seen a lot of discussion in the past and there are reasons for the current decision. I will see how I can make my code cope with reality.
Nathan Brendan Eich wrote: > Mariusz Nowak wrote: > > +1! > > > > It would be great if someone will explain in detail why > > Object.setPrototypeOf is no go. > > We've been over this many times, e.g. at > > https://mail.mozilla.org/pipermail/es-discuss/2012-May/022904.html > > To recap, > > 1. __proto__ is out in the field, a de-facto standard on "mobile", and > not going away. Adding another API doesn't help, it hurts. > > 2. SES and other secure subsets want same-frame (global object, "realm") > mashups of code that may use __proto__ and code that must not, but > Object.setPrototypeOf is a per-frame capability that would have to be > removed, breaking the former class of code. > > > > Any function that blindly extends object with provided hash is affected e.g. > > extend(obj, { __proto__: Error.prototype }). > > No, that depends on how extend works. If it uses Object.defineProperty > or equivalent, then nothing is broken and the setter on Object.prototype > for __proto__ is not run. > > > Additionally it means that we need to serialize any user input which > > eventually may be used as key on a dictionary e.g. data[userDefinedName]. > > Only if you use assignment into an object that delegates to > Object.prototype, but see (1) above: this hazard already exists. Don't > do that; JSON doesn't, and Object.create(null) gives a way to create > dictionaries. > > Yes, the problems you cite are real, but they are already part of the > de-facto __proto__ standard (1). Beyond that, Object.setPrototypeOf is a > mistake due to (2). > > /be > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
