On Aug 29, 2014, at 4:07 AM, André Bargull wrote: > ... > >> We checked with the recent ES6 draft but it seems to have the same issue. > > In ES6 it's actually possible to reach that step (8.1.1.2.6 GetBindingValue, > step 5), albeit it's a somewhat tricky and involves doing unusual things with > proxy objects: > > ,,, > Proxy objects allow you to define your own [[HasProperty]] implementation > (the "has" method in the example above). In this case [[HasProperty]] will > return `true` on the first call in order to report a binding is present in > HasBinding, but then will return `false` when the binding's presence is > checked the second time in GetBindingValue. >
And in ES5, host object have similar capabilities. I believe we put this checks in specifically to make sure everything was well defined in the presence of such host objects. Allen
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