Re: Iterating through an array (special syntax)

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From	Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups	comp.lang.javascript
Subject	Re: Iterating through an array (special syntax)
Date	Fri, 20 Oct 2017 21:48:07 +0200
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Rolf Niepraschk wrote:

> Am 19.10.2017 um 21:53 schrieb Thomas 'PointedEars' Lahn:
>> Unless oldItems.length changes,
>> 
>>    for (var i=0, len = oldItems.length; i < len; i++) {
>> 
>> is more efficient.
> 
> Are you sure?

Yes.  It is most obvious in the DOM.

> I see no much differences (at least with nodejs 8):
> [test with an *empty* loop over only 100'000 elements]

That does not mean anything; for example, sometimes internal optimization 
will take place, too.  Your empty loops are prime candidates for internal 
optimization to begin with.

My statement is true in general (as a rule of thumb), and if you think more 
carefully about it (i.e., how the “for” command works), you will realize 
why.

> I will think about your Promise solution. Thanks for your explanation.

You’re welcome.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | <http://PointedEars.de/es-matrix>
<https://github.com/PointedEars> | <http://PointedEars.de/wsvn/>
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Thread

Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-17 12:39 +0200
  Re: Iterating through an array (special syntax) "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-10-17 05:54 -0700
    Re: Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-17 15:03 +0200
      Re: Iterating through an array (special syntax) "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-10-17 06:19 -0700
        Re: Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-17 18:46 +0200
          Re: Iterating through an array (special syntax) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-10-18 13:55 +0200
            Re: Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-18 14:25 +0200
              Re: Iterating through an array (special syntax) "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-10-18 15:38 +0200
              Re: Iterating through an array (special syntax) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-10-18 15:49 +0200
          Re: Iterating through an array (special syntax) "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-10-18 16:25 -0700
            Re: Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-19 07:50 +0200
            Re: Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-19 15:15 +0200
              Re: Iterating through an array (special syntax) Julio Di Egidio <julio@diegidio.name> - 2017-10-19 06:36 -0700
                Re: Iterating through an array (special syntax) Julio Di Egidio <julio@diegidio.name> - 2017-10-19 06:39 -0700
                Re: Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-19 18:16 +0200
                Re: Iterating through an array (special syntax) Julio Di Egidio <julio@diegidio.name> - 2017-10-19 18:55 -0700
              Re: Iterating through an array (special syntax) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-10-19 21:53 +0200
                Re: Iterating through an array (special syntax) Rolf Niepraschk <Rolf.Niepraschk@gmx.de> - 2017-10-20 07:55 +0200
                Re: Iterating through an array (special syntax) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-10-20 21:48 +0200
  Re: Iterating through an array (special syntax) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-10-18 04:50 +0200

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