A DOM use case that can't be emulated with direct proxies
brendan at mozilla.com
Thu Dec 13 23:25:24 PST 2012
Mark S. Miller wrote:
> On Thu, Dec 13, 2012 at 7:05 PM, Brendan Eich<brendan at secure.meer.net> wrote:
>> Boris Zbarsky pointed out on public-script-coord that window.location and
>> window.document must be non-configurable _ab initio_, but perhaps this is
>> achievable with direct proxies?
> This resolved into two suggestions, both consistent with ES5 and with
> direct proxies:
> * windows.document and window.location must refuse to be configured,
> but they can still claim to be configurable. ES5 purposely forbids
> only the opposite mismatch: They can't claim to be non-configurable
> but still change state in ways that violate that claim.
> * Allen suggested that these could be non-configurable getter-only
> accessor properties,
window.location can be set by assignment to navigate to a new URL. Yet
it appears in Chrome, Firefox, Opera, and Safari to be a writable data
property. In any event, it can't be a getter-only accessor.
> where the getter stays the same and the magic
> "switching" behavior is in the getter. (My words for Allen's
> Either is fine. I like Allen's better.
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