Catch-all proposal based on proxies

Brendan Eich brendan at
Fri Dec 11 09:31:49 PST 2009

On Dec 11, 2009, at 8:36 AM, Maciej Stachowiak wrote:

> On Dec 10, 2009, at 10:06 PM, Mark S. Miller wrote:
>> has 263. I will proceed to worry only about hasOwnProperty until  
>> someone objects.
> Note that these are hits found in source repositories, not on the  
> Web. So I would not put too much stock in the number of hits except  
> as an existence proof. Both of these include hits from JavaScript  
> libraries, likely meaning there are many deployed copies of the code  
> in question (though unclear if that code path gets hit as the JS  
> libraries are used in practice).

Absolutely. The best case with codesearch would be to get no results  
-- that would suggest but not prove that the construct is not used.  
Getting any hits casts doubt on claim that the construct isn't used  
enough to worry about. More than a few handfuls of hits -> you should  

Mark, I don't think we can pick meta-level methods to worry about and  
not worry about, if the goal is transparent wrapping or catch-all  
based DOM emulations. OTOH, propertyIsEnumerable is much less used  
than hasOwnProperty, whether directly or via .call. But in principle  
it is the same kind of animal.


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