The incompatibility you've noticed is just a spec bug in
[[HasIntegrity]]. In step 2a of 8.3.3, the value of [[Extensible]] needs
to be inverted. With that change applied, the code snippet will return
`true`.
- André
------------------------------------------------------------------------
Hi,
Allen's latest draft (Rev. 14) contains the change where
[[Freeze]],[[Seal]] and [[PreventExtensions]] have been consolidated into
[[HasIntegrity]]/[[SetIntegrity]]. While no changes were made to the Proxy
API (i.e. no has/getIntegrity traps yet), the definition of
Object.{freeze,seal,preventExtensions} did change, and this is sufficient
to expose an incompatibility with ES5, namely:
Object.isFrozen(Object.preventExtensions({})) // true in ES5, false in ES6
Rev14 draft
I still feel like the consolidation isn't worth this incompatibility.
Allen, could you clarify what your intent is? Is it your intent that this
incompatibility will be fixed with further spec changes?
Cheers,
Tom
2013/2/21 Brendan Eich <brendan at mozilla.com
<https://mail.mozilla.org/listinfo/es-discuss>>
>/ Tom Van Cutsem wrote:
/>/
/>>/ That said, I don't think this is enough evidence either for or against
/>>/ the breaking change.
/>>/
/>/
/>/ I have a hard time believing we can break ES5. It has been shipping for
/>/ years (plural, at least in one case) in major browsers that evergreen their
/>/ user bases.
/>/
/>/ /be
/>
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