Re: x === x

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From	Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups	comp.lang.javascript
Subject	Re: x === x
Date	Wed, 31 May 2017 12:39:50 +0200
Organization	PointedEars Software (PES)
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Ben Bacarisse wrote:

> Thomas 'PointedEars' Lahn <PointedEars@web.de> writes:
>> Stefan Ram wrote:
>>> Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
>>>> What's wrong with {} === {}?
>>>   It depends on the context.
>> No, it does not.  “===” *makes* the (expression) context.
> 
> $ nodejs -c -e '[] === [];' && echo "ok"
> ok
> $ nodejs -c -e '{} === {};' && echo "ok"
> [eval]:1
> {} === {};
>    ^^^
> 
> SyntaxError: Unexpected token ===
> <snip trace-back>
> $ nodejs -c -e '({} === {});' && echo "ok"                        ✘
> ok

Fascinating.  I had tried in the Chrome DevTools Console, and there the 
trailing semicolon makes the difference:

| > {} === {}
| <- false
| {} === {};
| (x) Uncaught SyntaxError: Unexpected token ===

I assume that the explicit semicolon there is considered an /EmptyStatement/ 
that switches back to statement context.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | <http://PointedEars.de/es-matrix>
<https://github.com/PointedEars> | <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | Please do not cc me./Bitte keine Kopien per E-Mail.

Thread

Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-30 14:34 +0100
  Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-30 15:02 +0100
  Re: x === x Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-30 16:22 +0200
    Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-31 01:02 +0100
      Re: x === x Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-31 12:39 +0200
        Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-31 21:52 +0100
          Re: x === x Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-31 23:39 +0200
            Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-01 01:46 +0100
              Re: x === x Julio Di Egidio <julio@diegidio.name> - 2017-06-01 00:14 -0700
                Re: x === x John G Harris <niam@jghnorth.org.uk.invalid> - 2017-06-01 10:39 +0100
                Re: x === x Julio Di Egidio <julio@diegidio.name> - 2017-06-01 03:37 -0700
                Re: x === x John G Harris <niam@jghnorth.org.uk.invalid> - 2017-06-01 18:54 +0100
                Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-01 21:54 +0100
                Re: x === x John G Harris <niam@jghnorth.org.uk.invalid> - 2017-06-02 11:06 +0100
                Re: x === x John G Harris <niam@jghnorth.org.uk.invalid> - 2017-06-02 11:08 +0100
                Re: x === x John G Harris <niam@jghnorth.org.uk.invalid> - 2017-06-02 10:56 +0100
                Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-04 12:50 +0100
                Re: x === x John G Harris <niam@jghnorth.org.uk.invalid> - 2017-06-04 14:30 +0100
                Re: x === x Dr J R Stockton <J.R.Stockton@physics.org> - 2017-06-04 09:03 -0700
                Re: x === x Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-01 14:45 +0100
                Re: x === x Julio Di Egidio <julio@diegidio.name> - 2017-06-01 07:00 -0700
        Re: x === x Julio Di Egidio <julio@diegidio.name> - 2017-06-01 00:00 -0700

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