Le 13 sept. 2014 à 14:19, Claude Pache <[email protected]> a écrit :
> > Le 13 sept. 2014 à 11:47, Claude Pache <[email protected]> a écrit : > >> Hi, >> >> As noted some time ago, there is an issue with `Object.defineProperty` when >> it happens that someone has the facetious idea to give some value to >> `Object.prototype.get` [1]. >> >> While it is hardly an issue in day-to-day programming, I think that it is a >> good idea to make sure that specialized API (Reflect, proxy traps) are >> robust by design against that bug^H^H^H feature. Concretely, I propose: >> >> (1) proxy.[[DefineOwnProperty]] — When a proxy defines the corresponding >> trap, it shall receive an object with no prototype as property descriptor. >> >> (2) Reflect.getOwnPropertyDescriptor —That method shall return an object >> with no prototype, so that it can be readily used elsewhere, e.g. in >> Reflect.defineProperty. >> >> —Claude >> >> [1] >> http://esdiscuss.org/topic/object-prototype-get-bye-bye-object-defineproperty > > One can also (either alternatively or in addition) correct the other end of > the API: (1) in proxy.[[GetOwnProperty]], ignore non-own properties of the > result of the trap, and (2) in Reflect.defineProperty, ignore non-own > properties of the object descriptor. > > The core problem is that the two internal operations that convert between an > internal representation of a property descriptor on the one side, and a > concrete object representing a property descriptor on the other side, are not > the inverse one of the other, because of the interference of Object.prototype. > > —Claude Sorry for the spam, but I thought that a concrete example is good to illustrate the issue. Currently, under the assumption that someone will write `Object.prototype.get = function() {}`, the following proxy: Proxy(target, { defineProperty: (target, prop, desc) => Reflect.defineProperty(target, prop, desc) , getOwnPropertyDescriptor: (target, prop) => Reflect.getOwnPropertyDescriptor(target, prop) }) is broken, and the following code: desc = Reflect.getOwnPropertyDescriptor(source, prop) if (desc) status = Reflect.defineProperty(target, prop, desc) is broken as well. —Claude _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
