Re: How would you prepare for javascripting interview?

From	Doc O'Leary <droleary@2015usenet1.subsume.com>
Newsgroups	comp.lang.javascript
Subject	Re: How would you prepare for javascripting interview?
Date	2016-09-06 16:02 +0000
Organization	Subsume Technologies, Inc.
Message-ID	<nqmpag$kit$1@dont-email.me> (permalink)
References	(5 earlier) <1875389.irdbgypaU6@PointedEars.de> <nn044b$e69$1@dont-email.me> <nqf8t7$h37$1@dont-email.me> <nqhg6o$st6$1@dont-email.me> <nqkl2e$6bt$1@dont-email.me>

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For your reference, records indicate that 
Scott Sauyet <scott@sauyet.com> wrote:

> I disagree.  The realistic choices are
> 
>   (A) Return something of the correct type, even though it's not 
>       in the (empty) input list.
> 
>   (B) Return some semaphore of a different type that signals that 
>       things have gone wrong: `undefined` or `null` are most likely.
> 
>   (C) Throw an error.
> 
> None of these choices is ideal, but we have to choose between them.  I'd
> say that the best ordering is A > C > B.

Then I wonder if you’ve ever done any sort of sophisticated 
programming.  There is a *reason* why languages developed mechanisms 
other than “return a valid value and let the programmer figure out 
if it’s *actually* a good result, or just some kind of error”.

> Of course this is better for numbers than for some other types because 
> numbers specifically encompass maximum and minimum values of their type.  
> But this is the `Math` API.  Why should it not speak to the number type?

It’s best dealt with abstractly, because the concept applies to 
things other than numbers.  If you can order it, you can determine 
a “max” value.  And if there is *no* values to order, it is ludicrous 
to say the correct result is a valid value you have simply fabricated.

But even restricted to numbers, the abuse of infinity remains an 
implementation hack.  NaN is also a number, and also already used 
by min/max to signal an error.  It makes zero sense (beyond the 
hack) to return an infinity.

> Since the second choice in my hierarchy is to throw an error, I think it 
> would be reasonable to do so if the type does not permit a reasonable 
> maximum or minimum value.  For Javascript, only three ordered types come 
> to mind: Numbers, Dates, and Strings, although I may be missing some.  

You’re missing an infinity of objects that developers can define 
for themselves.  Or just the infinity of uses a Number can have.  
You’re stuck thinking about the objects you have rather than the 
*uses* the objects are put to.  Stop and actually *think* about 
what you actually have to do to write a program that behaves 
properly when you define functions that fabricate “valid” results.

> Dates have an underlying fixed bit-sized number, so we could easily do 
> the same for Dates.  An imaginary `String.max()` could be satisfied with 
> the empty String, but `String.min()` would be much harder; I think it 
> would have to throw.

That’s an utter mess.  You should never be allowed to write a 
software library that is used by anyone else.

> It's not that I think this is a bad point. I simply don't believe it's as 
> clear-cut as described.

It is.  Perhaps one day you’ll be experienced enough to understand 
why.

> > They’ll have to do worse if they expect to function correctly based on
> > the current behavior.  You could perhaps raise it as an exception if you
> > prefer, but it’s just plain *wrong* to return a number that wasn’t given
> > to you.  
> 
> Garbage in, garbage out.  It's no more wrong to do this than to supply a 
> function that needs a non-empty list with an empty one.  I assume that 
> you would rather throw in this case or to return `null` or `undefined`.  

I would seek to define a consistent behavior.  The *way* garbage 
comes out is important.  That’s the entire issue of why an infinity 
is the wrong result.

> To my mind, either of these is significantly worse.  By returning a 
> number, you allow the user to proceed with numeric calculations, 
> including, most importantly, using this result in a further max or min 
> calculation.  (This is very much related to the arguments that Stefan Ram 
> has made.)

Compounded errors are not the better solution.  I want to know when 
and where something went wrong, not just *guess* at when the final 
result looks a bit off.

> > That’s why this behavior makes for a suitable trick question,
> > but a terrible one for finding a JavaScript developer that actually
> > thinks about the work they’re doing.
> 
> But remember the context of this question: I've already determined that 
> the candidate has reasonably strong skills in Javascript.

I doubt you objectively have.

> This is not a trick question in the sense that I'm asking the candidate 
> about the esoterica of the language; I'm not asking her to explore 
> obscure corners of the spec.

But that’s exactly what you’re doing.  You’re asking them about a 
hack that has, unfortunately, remained in the Math object for far 
too long.  If you legitimately want them to think, you’d do 
something like I have done, and explore ways to provide a min/max 
function for abstract collections of any type.  My bet is that none 
but the *least* qualified candidates will come up with solutions 
that fabricate results the way Math does for numbers.

-- 
"Also . . . I can kill you with my brain."
River Tam, Trash, Firefly

Thread

How would you prepare for javascripting interview? justaguy <lichunshen84@gmail.com> - 2016-07-18 09:10 -0700
  Re: How would you prepare for javascripting interview? Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2016-07-18 18:37 +0200
    Re: How would you prepare for javascripting interview? justaguy <lichunshen84@gmail.com> - 2016-07-18 11:09 -0700
      Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-07-21 01:04 +0000
        Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-07-21 14:24 +0100
        Re: How would you prepare for javascripting interview? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-07-23 16:25 +0200
          Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-07-23 15:56 +0000
            Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-03 19:39 +0000
              Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-04 15:56 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-05 00:06 +0100
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-05 14:49 +0100
                Re: How would you prepare for javascripting interview? $Bill <news@todbe.com> - 2016-09-05 10:01 -0700
                Re: How would you prepare for javascripting interview? Gene Wirchenko <genew@telus.net> - 2016-09-06 09:36 -0700
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-05 15:05 +0100
                Re: How would you prepare for javascripting interview? Andreas Bergmaier <andber93@web.de> - 2016-09-05 20:31 +0200
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-06 15:15 +0000
                Re: How would you prepare for javascripting interview? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-09-06 19:40 +0200
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-06 19:25 +0100
                Re: How would you prepare for javascripting interview? Andreas Bergmaier <andber93@web.de> - 2016-09-06 22:16 +0200
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-07 17:17 +0100
                Re: How would you prepare for javascripting interview? Andreas Bergmaier <andber93@web.de> - 2016-09-07 20:07 +0200
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-08 14:36 +0100
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-05 18:46 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-05 20:32 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-05 17:27 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-05 20:12 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-06 16:48 +0000
                Re: How would you prepare for javascripting interview? Andreas Bergmaier <andber93@web.de> - 2016-09-06 19:56 +0200
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-07 20:16 +0000
                Re: How would you prepare for javascripting interview? Gene Wirchenko <genew@telus.net> - 2016-09-07 10:01 -0700
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-07 20:21 +0000
                Re: How would you prepare for javascripting interview? Gene Wirchenko <genew@telus.net> - 2016-09-09 11:41 -0700
                Re: How would you prepare for javascripting interview? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2016-09-09 15:35 -0700
                Re: How would you prepare for javascripting interview? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2016-09-09 20:40 -0700
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-10 15:12 +0000
                Re: How would you prepare for javascripting interview? Gene Wirchenko <genew@telus.net> - 2016-09-12 11:14 -0700
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-13 21:07 +0000
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-06 16:20 +0000
                Re: How would you prepare for javascripting interview? Ken Tilton <kentilton@gmail.com> - 2016-09-05 11:37 -0700
                Re: How would you prepare for javascripting interview? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-09-06 19:26 +0200
                Re: How would you prepare for javascripting interview? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2016-09-08 12:41 -0700
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-05 20:37 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-05 22:13 +0100
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-06 02:33 +0000
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-06 16:02 +0000
                Re: How would you prepare for javascripting interview? Gene Wirchenko <genew@telus.net> - 2016-09-06 09:50 -0700
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-07 01:36 +0000
                Re: How would you prepare for javascripting interview? Gene Wirchenko <genew@telus.net> - 2016-09-07 10:07 -0700
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-10 00:03 +0000
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-10 00:12 +0000
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-10 15:34 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-11 01:32 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-12 19:26 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-13 01:02 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-13 21:38 +0000
                Re: How would you prepare for javascripting interview? "Christoph M. Becker" <cmbecker69@arcor.de> - 2016-09-14 00:56 +0200
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-15 15:09 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-14 00:47 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-15 15:34 +0000
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-11 02:45 +0000
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-12 19:10 +0000
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-12 21:06 +0100
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-07 03:12 +0000
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-07 19:53 +0000
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-10 02:14 +0000
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-10 11:25 +0100
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-10 15:49 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-10 18:39 +0000
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-11 02:45 +0000
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-11 16:23 +0100
                Re: How would you prepare for javascripting interview? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-12 20:32 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-12 18:49 +0000
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-13 00:27 +0000
                Re: How would you prepare for javascripting interview? Tim Streater <timstreater@greenbee.net> - 2016-09-13 08:51 +0100
                Re: How would you prepare for javascripting interview? Jon Ribbens <jon+usenet@unequivocal.eu> - 2016-09-13 12:33 +0000
                Re: How would you prepare for javascripting interview? Scott Sauyet <scott@sauyet.com> - 2016-09-14 01:17 +0000
                Re: How would you prepare for javascripting interview? Tim Streater <timstreater@greenbee.net> - 2016-09-14 11:15 +0100
                Re: How would you prepare for javascripting interview? Doc O'Leary  <droleary@2015usenet1.subsume.com> - 2016-09-15 15:02 +0000
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-13 10:06 +0100
                Re: How would you prepare for javascripting interview? John Harris <niam@jghnorth.org.uk.invalid> - 2016-09-06 19:53 +0100
    Re: How would you prepare for javascripting interview? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-07-18 22:30 +0200
  Re: How would you prepare for javascripting interview? justaguy <lichunshen84@gmail.com> - 2016-07-18 14:56 -0700
  Re: How would you prepare for javascripting interview? Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2016-07-19 16:01 -0300
    Re: How would you prepare for javascripting interview? Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2016-07-19 16:16 -0300

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