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Groups > comp.lang.javascript > #27332

Re: Puzzling JS Error

From Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups comp.lang.javascript
Subject Re: Puzzling JS Error
Date 2015-04-12 01:07 +0200
Organization PointedEars Software (PES)
Message-ID <9301741.hI6YXm1qAv@PointedEars.de> (permalink)
References (2 earlier) <1798717.ojboOnzLPd@PointedEars.de> <mgc2hl$e88$1@speranza.aioe.org> <2172415.g2VhMMEByA@PointedEars.de> <mgc75b$or6$1@speranza.aioe.org> <6827636.tojzTVapKU@PointedEars.de>

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Thomas 'PointedEars' Lahn wrote:

> You are talking about the wrong recommendation of
> 
>   if (jsx.net === undefined)
> 
> of JS*L*int.  It is wrong because the “undefined” property of the global
> object has been writable before,

… – and because

  typeof x != "undefined"

is _not_ functional equivalent to

  x !== undefined

even if the value of the “undefined” property is the default of type 
Undefined.  Because the latter throws a ReferenceError exception if “x” 
cannot be resolved, the former does not – …

> but Douglas Crockford is either unaware of that or chooses to ignore it, 
> like so many other issues.  Avoid JSLint.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
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Thread

Puzzling JS Error "Mel Smith" <syntel@cox.net> - 2015-04-09 11:49 -0600
  Re: Puzzling JS Error "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-04-09 22:21 +0200
    Re: Puzzling JS Error "Mel Smith" <syntel@cox.net> - 2015-04-09 16:26 -0600
      Re: Puzzling JS Error "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-04-10 10:32 +0200
      Re: Puzzling JS Error Denis McMahon <denismfmcmahon@gmail.com> - 2015-04-10 14:51 +0000
        Re: Puzzling JS Error "Mel Smith" <syntel@cox.net> - 2015-04-10 09:48 -0600
          Re: Puzzling JS Error "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-04-10 18:01 +0200
  Re: Puzzling JS Error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-10 00:20 +0200
  Re: Puzzling JS Error JJ <jj4public@vfemail.net> - 2015-04-10 11:15 +0700
    Re: Puzzling JS Error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-11 16:15 +0200
      Re: Puzzling JS Error Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-04-11 18:09 -0300
        Re: Puzzling JS Error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-11 23:42 +0200
          Re: Puzzling JS Error Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-04-11 19:27 -0300
            Re: Puzzling JS Error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-12 01:01 +0200
              Re: Puzzling JS Error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-12 01:07 +0200
                Re: Puzzling JS Error Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-04-11 22:07 -0300

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