fail-fast object destructuring

Brendan Eich brendan at
Thu Jul 5 15:47:10 PDT 2012

Claus Reinke wrote:
>> Allen rallied me to the prefix-! route by objecting that prefix-? 
>> would not be available outside of patterns, which simply highlights 
>> how JS already imputes undefined for missing property.
> Could you expand on this? Refutable vs irrefutable only applies to 
> patterns so far, though one could imagine property selectors with
> early failure to complement the current succeed-with-undefined.

Allen's post is up-thread about 14 messages:


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