2012/11/24 David Bruant <[email protected]> > Le 23/11/2012 18:48, Allen Wirfs-Brock a écrit : > > Added Keys, [[OwnPropertyKeys]], [[Freeze]], [[Seal]], [[IsFrozen]], > [[IsSealed]]. > > For both the enumerations and the layer on top of [[PreventExtension]], > I'm uneasy. > * [[Enumerate]], [[Keys]] and [[OwnPropertyKeys]] are very close operations > * So are [[PreventExtensions]]/[[Freeze]]/[[Seal]] on one side and > [[IsExtensible]]/[[IsFrozen]]/[[IsSealed]] > > I'm afraid that making them distinct operations increases footgun-ness. > [[HasProperty]] has been removed in favored of [[HasOwnProperty]] (which > might be removed in favor of only keeping [[GetOwnProperty]], though the > conclusion of the discussion was the keep both IIRC) because the former > could be "robustly" composed between >
The way I see it: - we have no way of enforcing fully internally consistent proxies anyway - even with some traps removed (such as "has"), opportunities for inconsistencies abound - thus, why be selective and try to combat some inconsistencies while letting others slip by? The Handler API seems an adequate solution to avoid the footgun of trap inconsistencies. > > • instanceof operator no longer uses an internal method. Instead, > extensible via a @@hasInstance symbol-keyed regular method. > > I don't remember a discussion on this topic, but I think it's an > interesting change. Is it for browser APIs? > There might be an associated security worry here if any object can have > its @@hasInstance changed, but one good thing is that the debate of > trapping instanceof ends if it's a symbol-keyed method. > I don't think there's a security issue: can't symbol-keyed properties also be made non-configurable? Cheers, Tom
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