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Re: eventDispath how that work

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Thomas 'PointedEars' Lahn wrote:

> Incidentally, at work today I encountered, essentially, this piece of code
> written by someone else:
> 
>   if (window.toString.call(…) == "[object Array]") {
>     // …
>   }
> 
> (Obviously an attempt to detect whether an value would be a reference to
> an Array instance, which is in many cases a misguided one [see “duck
> typing” for details].)
> 
> It failed reproducibly in Internet Explorer 8 (with the infamous “error
> code 0”) on Windows XP¹ because there was no “window.toString”, and that
> caused *other* code (a progress indicator) to not function (a
> JScript/MSHTML peculiarity).
> 
> For now, I can see three possible explanations how this code came about
> (I will investigate this tomorrow morning):
> 
> […]
>   C. Someone thought “window” would refer to the native ECMAScript global
>      object and would therefore have a built-in “toString” method.

I must assume that this was it.  The code above failed because the *host* 
object referred to by “window” did have a built-in “toString” method that 
you could call (it returned "[object]" then), but the referred callable 
*host* object did not have a “call” method itself.

After I replaced “window” with a reference to an Object instance (here: 
dict) – a *native* object –, that part of the code worked again in IE 8:

  if (dict.toString.call(…) == "[object Array]") {
    // …
  }

Because the Object instance inherited its “toString” method from the 
*native* object referred to by “Object.prototype” which, as per 
Specification, has a “toString” method that is a Function instance – a 
*native* object.  That, in turn, inherits a “call” method from the *native* 
object referred to by “Function.prototype”.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not Cc: me. / Bitte keine Kopien per E-Mail.

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eventDispath how that work Une Bévue <unbewusst.sein@fai.invalid> - 2014-10-14 16:23 +0200
  Re: eventDispath how that work JJ <jj4public@vfemail.net> - 2014-10-15 03:24 +0700
    Re: eventDispath how that work Une Bévue <unbewusst.sein@fai.invalid> - 2014-10-15 10:49 +0200
    Re: eventDispath how that work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-10-15 15:24 +0200
      Re: eventDispath how that work JJ <jj4public@vfemail.net> - 2014-10-16 02:10 +0700
        Re: eventDispath how that work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-10-15 23:02 +0200
          Re: eventDispath how that work Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-10-15 18:59 -0300
            Re: eventDispath how that work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-10-16 02:48 +0200
          Re: eventDispath how that work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-10-16 18:11 +0200
      Re: eventDispath how that work Une Bévue <unbewusst.sein@fai.invalid> - 2014-10-15 22:06 +0200
        Re: eventDispath how that work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-10-15 23:39 +0200
          Re: eventDispath how that work Une Bévue <unbewusst.sein@fai.invalid> - 2014-10-16 14:26 +0200
            Re: eventDispath how that work Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-10-16 14:39 -0300
              Re: eventDispath how that work Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-10-16 19:44 -0300
                Re: eventDispath how that work Une Bévue <unbewusst.sein@fai.invalid> - 2014-10-17 09:00 +0200
                Re: eventDispath how that work Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-10-17 10:16 -0300
                Re: eventDispath how that work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-10-17 21:40 +0200
                Re: eventDispath how that work Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-10-17 17:03 -0300
                Re: eventDispath how that work Une Bévue <unbewusst.sein@fai.invalid> - 2014-10-18 15:46 +0200
              Re: eventDispath how that work Une Bévue <unbewusst.sein@fai.invalid> - 2014-10-17 08:26 +0200

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