Groups > comp.lang.javascript > #19841

Re: jslint and typeof

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From	Thomas 'PointedEars' Lahn <PointedEars@web.de>
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Subject	Re: jslint and typeof
Newsgroups	comp.lang.javascript
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Eric Bednarz wrote:

> "Jukka K. Korpela" <jkorpela@cs.tut.fi> writes:
>> the test
>>
>> typeof options.actor !== "undefined"
>>
>> is unnecessary complicated, since you can use
>>
>> options.action !== undefined
> 
> This, however, is unnecessarily brittle since the undefined property of
> the global object is writable in ES < 5.

ACK.  And in earlier implementations there was no “undefined” property, 
causing this to throw (the equivalent of) a ReferenceError.

> It is also overly verbose.

In what way?

> options.action !== void 0;

I would call *that* overly verbose.  For backwards compatibility, I have 
occasionally declared

  var undefined;

However, nowadays the “!==” and “===” operators and the “undefined” property 
of the Global Object can generally be considered safe language features.  
Only a caveat with the property value and host objects must remain for the 
time being.

-- 
PointedEars

Twitter: @PointedEars2
Please do not Cc: me. / Bitte keine Kopien per E-Mail.

Thread

jslint and typeof Andrew Poulos <ap_prog@hotmail.com> - 2013-05-20 19:59 +1000
  Re: jslint and typeof "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2013-05-20 13:40 +0300
    Re: jslint and typeof Eric Bednarz <bednarz@fahr-zur-hoelle.org> - 2013-05-20 13:34 +0200
      Re: jslint and typeof Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-05-20 14:23 +0200
        Re: jslint and typeof Eric Bednarz <bednarz@fahr-zur-hoelle.org> - 2013-05-26 17:40 +0200
  Re: jslint and typeof Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-05-20 13:48 +0200
  Re: jslint and typeof Stefan Weiss <krewecherl@gmail.com> - 2013-05-20 14:44 +0200
    Re: jslint and typeof Andrew Poulos <ap_prog@hotmail.com> - 2013-05-20 23:17 +1000

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