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Groups > comp.lang.javascript > #33621

Re: timeline

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Andrew Poulos wrote:

> var timeline = ["a", "b", "c",...];
> 
> where "a" "b" are the names of the functions to call and control code
> that looks like
> 
> var position = 0;
> 
> function runTimeline() {
>    position = (position == timeline.length ? position : 0);
>    window.timeline[position]();

Never use “window” to refer to the global object; pass a reference to it 
instead:

  var timeline = ["a", "b", "c",...];

  function runTimeline (global)
  {
    // …
    global.timeline[position]();
  }

  runTimeline(this);

That said, avoid global variables and functions, and referring to the global 
object, in the first place.

>    position++;
> }
> 
> function a() {
>    // do stuff and then when done
>    runTimeline();
> }
> function b() {
>    // do stuff and then when done
>    runTimeline();
> }
> 
> Is that a workable approach

I do not think so.  All of this still runs in a single thread, so you would 
be blocking the browser/tab.  Also, consider stack overflow:

  runTimeline()
    a()
      runTimeline()
        b()
          runTimeline()
            …
  
And I do not see how you would prevent items from being displayed earlier, 
before they are fully loaded, this way.

> or is there a better/smarter way?

As should be obvious now, *anything* is better/smarter than this.

ISTM that ultimately you will want to use the Promise pattern, triggering 
the next step only when the previous step has been completed *and* the 
required resources have been loaded (i.e. the Promise has been fulfilled).  
Built-in Promise support was just added in ECMAScript 2016, so you will 
probably have to use a framework (pre-existing or your own implementation) 
to make it work in all of your target environments.

-- 
PointedEars
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Thread

timeline Andrew Poulos <ap_prog@hotmail.com> - 2017-07-20 18:17 +1000
  Re: timeline "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-07-20 10:26 +0200
  Re: timeline Wally W. <ww84wa@aim.com> - 2017-07-20 08:37 -0400
    Re: timeline Andrew Poulos <ap_prog@hotmail.com> - 2017-07-21 07:47 +1000
      Re: timeline Wally W. <ww84wa@aim.com> - 2017-07-20 23:04 -0400
        Re: timeline Andrew Poulos <ap_prog@hotmail.com> - 2017-07-21 16:08 +1000
          Re: timeline "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-07-21 11:36 +0200
            Re: timeline Julio Di Egidio <julio@diegidio.name> - 2017-07-21 08:50 -0700
              Re: timeline "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-07-22 00:03 +0200
            Re: timeline Andrew Poulos <ap_prog@hotmail.com> - 2017-07-22 15:00 +1000
              Re: timeline "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-07-22 10:19 +0200
                Re: timeline Andrew Poulos <ap_prog@hotmail.com> - 2017-07-23 09:08 +1000
                Re: timeline "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-07-23 10:15 +0200
  Re: timeline "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-07-20 05:56 -0700
    Re: timeline Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-07-23 19:07 +0200
  Re: timeline Julio Di Egidio <julio@diegidio.name> - 2017-07-20 05:59 -0700
  Re: timeline Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-07-23 18:57 +0200
    Re: timeline Julio Di Egidio <julio@diegidio.name> - 2017-07-23 10:33 -0700

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