On Thu, Dec 10, 2009 at 4:42 PM, Mark S. Miller <[email protected]> wrote:
> On Wed, Dec 9, 2009 at 11:26 PM, Mike Samuel <[email protected]> wrote: > >> On the climbing the meta, I'd like to understand how this might >> interact with other proposals. >> >> get - already can execute arbitrary code due to getters >> set - already can execute arbitrary code due to setters >> in - cannot for non host objects >> delete - cannot for non host objects >> enumerate - cannot for non host objects >> > > By the currently proposed taxonomy at < > http://wiki.ecmascript.org/doku.php?id=strawman:proxies#interaction_of_external_methods_and_proxies>, > all the above are base-level operations. The list at < > http://wiki.ecmascript.org/doku.php?id=strawman:proxies#climbing_the_meta_ladder> > explains that all the above can cause user code to execute whereas the last > three, as you point out, currently cannot. > > > >> hasOwnProperty - cannot for non host objects >> >> Incidentally, is Object.prototype.hasOwnProperty(myProxy) >> O(myProxyHandler.keys().length) for proxies? This seems bad since a >> for (in) loop that filters out non-own properties would be O(n**2) on >> top of the loop body. >> > > By the current taxonomy, Object.prototype.hasOwnProperty(myProxy) is > meta-level and always returns false on a trapping proxy, revealing that it > does not actually have any own properties. > > Arrg! That should be Object.prototype.hasOwnProperty.call(myProxy, name). aProxy.hasOwnProperty(name) will of course trap as you'd expect, and so is base level. > > -- > Cheers, > --MarkM > -- Cheers, --MarkM
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