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Groups > comp.lang.javascript > #33183

Re: Object.defineProperties

From Cezary Tomczyk <cezary.tomczyk@gmail.com>
Newsgroups comp.lang.javascript
Subject Re: Object.defineProperties
Date 2017-05-03 18:47 +0200
Organization csiph.com Internet News Service
Message-ID <oed1ip$bg1$1@csiph.com> (permalink)
References (3 earlier) <class-20170503094344@ram.dialup.fu-berlin.de> <oec665$2g1c$1@csiph.com> <class-20170503102120@ram.dialup.fu-berlin.de> <oecbqt$2l61$1@csiph.com> <type-tags-20170503130718@ram.dialup.fu-berlin.de>

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On 03/05/2017 14:07, Stefan Ram wrote:
> Cezary Tomczyk <cezary.tomczyk@gmail.com> writes:
>> So, I can't trust what's returned by
>> Object.prototype.toString.call(obj). However, if I want to check what
>> type is an object then I can use typeof operator, but it's not quite
>> thing I want as the typeof for object type array give me "object".
>
>   I just had this idea: You can tag each prototype with your
>   own tag symbol: For example, to tag the String prototype:
>
> |> let myTag = Symbol( "myTag" );
> |> Object.getPrototypeOf( "" )[ myTag ] = "String"
>
>   Now, when we have any object, we can check its prototype for
>   our tag:
>
> |> Object.getPrototypeOf( "abc" )[ myTag ]
>
>   . No one else can mess with our tag, because they don't have
>   the symbol!
>
>   At least it seems to work for numbers and strings here:
>
> |> Object.getPrototypeOf( 1 )[ myTag ]= "Number"
>
> |> Object.getPrototypeOf( 2 )[ myTag ]
> |< Number
>
> |> Object.getPrototypeOf( "abc" )[ myTag ]
> |< String

Interesting approach. It seems it's working. Thanks.

Let's see if anyone else would have a different idea.

-- 
Cezary Tomczyk
http://www.ctomczyk.pl/
https://www.aslint.org/ - Accessibility validation tool

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Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-03 08:36 +0200
  Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-03 10:14 +0200
    Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-03 10:59 +0200
      Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-03 12:36 +0200
        Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-03 18:47 +0200
          Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-05 18:18 +0200
    Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-05 18:14 +0200
      Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-05 19:37 +0200
        Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-05 20:11 +0200
          Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-06 15:26 +0200
            Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-06 16:43 +0200
              Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-06 20:23 +0200
                Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-06 22:21 +0200
                Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-06 23:19 +0200
                Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-07 02:40 +0200
            Re: Object.defineProperties Stefan Weiss <krewecherl@gmail.com> - 2017-05-06 22:37 +0200
              Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-06 23:05 +0200
                Re: Object.defineProperties Stefan Weiss <krewecherl@gmail.com> - 2017-05-07 00:29 +0200
                Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-07 10:06 +0200
                Re: Object.defineProperties Stefan Weiss <krewecherl@gmail.com> - 2017-05-08 00:50 +0200
                Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-08 13:17 +0200
                Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-07 02:37 +0200
                Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-07 09:42 +0200
                Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-07 17:11 +0200
                Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-07 20:08 +0200
        Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-05 20:59 +0200
          Re: Object.defineProperties John G Harris <niam@jghnorth.org.uk.invalid> - 2017-05-06 10:35 +0100
  Re: Object.defineProperties Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2017-05-05 08:32 +0200
  Re: Object.defineProperties Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-05 18:24 +0200

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