More fun with undefined

Thaddee Tyl thaddee.tyl at
Thu Jun 14 15:35:41 PDT 2012

On Thu, Jun 14, 2012 at 3:29 PM, Allen Wirfs-Brock
<allen at> wrote:
> This is a different issue, but I wonder how badly the web would break if we
> made undefined a reserved word.  Does anybody in JS really declare a
> different local binding for undefined?  In ES5 we got away with making
> undefined read-only.  Maybe we should continue pushing and see if we can
> eliminate the rebindable undefined hazard.

JQuery [1] famously has an "undefined" parameter, like so:

    (function( window, undefined ) { … }(window))

What would happen in this case?


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