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From: Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups: comp.lang.javascript
Subject: Re: Date false
Date: Sat, 10 May 2014 10:36:22 +0200
Organization: PointedEars Software (PES)
Lines: 31
Message-ID: <9594146.3ms6Ipm6O6@PointedEars.de>
References: <1JidnUNwV7viyvHOnZ2dnUVZ_t6dnZ2d@westnet.com.au> <falsy-date-20140509065812@ram.dialup.fu-berlin.de> <lkjdnp$rfg$1@speranza.aioe.org> <ToBoolean-20140509231033@ram.dialup.fu-berlin.de>
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Xref: csiph.com comp.lang.javascript:24069

Stefan Ram wrote:

>   Since the OP apparently had an object, I wondered whether an object
>   can be made falsy somehow. The following did not work:
> 
> if( { valueOf: function (){ return false; }})document.writeln( 'a' );
> 
>   . »Not work« means that it wrote »a«.
> 
>   In fact, »9.2 ToBoolean« says that any object always is converted
>   to true,

No, it says that any *value of the Object type* is converted to “true”.

>   so I really do not understand how in the OP's
> 
> if( d )do_something();
> 
>   it is possible that »do_something();« is not executed, when d is
>   either a string (that is not equal to »""«) or an object.

As the “typeof” operation (§11.4.3) resulted in "date" – neither "object" 
nor "function" – we must assume that the value is of an additional type for 
which the “ToBoolean” algorithm has been augmented in the used 
implementation, according to §2 “Conformance”.

-- 
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