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Re: Differences between [[Class]] and constructor

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  Re: Differences between [[Class]] and constructor Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-06-02 22:58 +0200
    Re: Differences between [[Class]] and constructor Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-06-02 23:07 +0200

#27967 — Re: Differences between [[Class]] and constructor

Stefan Ram wrote:

>   I have observed that the class ([[Class]]) name

That is _not_ the “class name”, it is the value of the internal “[[Class]]” 
property of values.  “[[Class]]” is purely a Specification mechanism and 
does not need to be implemented in a way other than to satisfy the 
algorithms of the Specification.

>   and the constructor name of an object often is the same!

Often, but not always.  As specified.

> function className( object )
> { return 0,
>   Object.prototype.toString.call( object ).
>   replace( "\[object ", "" ).replace( "\]", "" ); }

This is written shorter, less error-prone, more efficient, and actually 
readable

  (({}).toString.call(object).match(/\[object\s+(.+)\s*\]/) || [])[0]

> let n = new Number( 3.14 );

  var n = Math.PI;
 
-- 
PointedEars
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Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
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#27969

Thomas 'PointedEars' Lahn wrote:

> Stefan Ram wrote:
>> function className( object )
>> { return 0,
>>   Object.prototype.toString.call( object ).
>>   replace( "\[object ", "" ).replace( "\]", "" ); }
> 
> This is written shorter, less error-prone, more efficient, and actually
> readable
> 
>   (({}).toString.call(object).match(/\[object\s+(.+)\s*\]/) || [])[0]

[1], of course.  (So much for “less error-prone” ;-))

-- 
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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