On Dec 15, 2012, at 9:21 AM, David Bruant wrote: > Hi, > > On public-script-coord, Boris Zbarsky showed an example [1] where a global > variable is var-defined and then observed to be absent from the global object > it was attached to (because the WindowProxy has changed of underlying window > object). > > The careful ECMAScript 5.1 reader knows that global var-defined variables are > supposed to be reflected as own non-configurable properties of the global > object. Reflecting the property as such commits the object to keep the > property forever which, as we've seen in Boris example, is not compatible > with how the web works. > > I don't think it'll be possible to change how global objects in same-origin > iframes work nor relax ES5 invariants; so my proposal is to have > var/let/const/function global declarations *reflected* as configurable, but > acting as if they were not. > This would also require a couple of changes in the spec and consequently JS > engines and certainly test262. > Other proposals welcome, of course.
Note that in ES6 global bindings introduced by let/const/class/import bound using a declarative environment record and will not be reflected at all on the global object. That still leaves any issues relating to var and function declarations. Allen _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
