@@symbol hooks and cross domain frames

In ES5 the following works:

  [].concat(windowFromOtherDomain)

But in ES6 it fails because reading @@isConcatSpreadable throws an
access denied error.

Similar issues arise with @@toStringTag and @@hasInstance

To stay web compatible we are thinking that if these [[Get]]s fail
their access check we treat the value as undefined.

There might also be similar issues with Get(x, "constructor") and
@@species but I believe all of them might be better of throwing.

-- 
erik

Received on Thursday, 9 July 2015 13:48:32 UTC