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Groups > comp.lang.javascript > #16837
| Message-ID | <6590377.0brVofrJPU@PointedEars.de> (permalink) |
|---|---|
| From | Thomas 'PointedEars' Lahn <PointedEars@web.de> |
| Organization | PointedEars Software (PES) |
| Date | 2012-10-24 21:27 +0200 |
| Subject | Re: Programming style question |
| Newsgroups | comp.lang.javascript |
| References | (8 earlier) <f5td88dckgks06mf02cssn9e0116qum6c8@4ax.com> <XnsA0F5E78026978eejj99@194.109.133.133> <722e889us0ep0mra233907giq2nnolqhge@4ax.com> <XnsA0F6619B1C3Ceejj99@194.109.133.133> <H8Cdnb-fM7uqoRXNnZ2dnUVZ_gydnZ2d@earthlink.com> |
| Followup-To | comp.lang.javascript |
Followups directed to: comp.lang.javascript
Patricia Shanahan wrote:
> On 10/24/2012 12:35 AM, Evertjan. wrote:
>> Well, you are looking the wrong way, it seems,
>> these oprators, especially || are regulary used
>> in Javascript to prevent errors when a function is not available
>> on a platform, so at runtime, when you as a programmer are not available.
>>
>> var r = aDOMfunction || aDOMfunction("23px");
>
> I've looked at this several times, and think it should be "&&" not "||".
>
> "||" evaluates the right hand side if the left hand side is not truthy,
> in this case if the function does not exist.
>
> Surely one wants to evaluate the right hand side if, and only if,
> aDOMfunction *does* exist. That is what "&&" would do.
Correct. It is insufficient and error-prone a feature test, though: A true-
value does not need to be callable, and a host object can throw an exception
on type conversion or even non-calling read access. Search for
implementations of `isNativeMethod' and `isHostMethod' instead (you can find
one in JSX:object.js).
`||' is useful for implementing default values, but slightly overkill for
default parameter values (unless they are not used left-hand side of the
assignment).
PointedEars
--
realism: HTML 4.01 Strict
evangelism: XHTML 1.0 Strict
madness: XHTML 1.1 as application/xhtml+xml
-- Bjoern Hoehrmann
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Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-18 08:32 +0100
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-18 10:23 +0200
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-18 13:42 +0100
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-18 17:59 +0200
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-18 09:56 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-19 00:49 +0200
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-19 11:04 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-20 11:52 +0200
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-19 12:06 -0700
Re: Programming style question Tim Streater <timstreater@greenbee.net> - 2012-10-19 23:12 +0100
Re: Programming style question "Mel Smith" <med_cutout_syntel@aol.com> - 2012-10-19 21:56 -0600
Re: Programming style question Bart Van der Donck <bart@nijlen.com> - 2012-10-20 02:21 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-20 12:03 +0200
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-20 06:31 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-20 18:30 +0200
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-20 10:32 -0700
Re: Programming style question Tim Streater <timstreater@greenbee.net> - 2012-10-20 22:34 +0100
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-21 10:12 +0200
Re: Programming style question Tim Streater <timstreater@greenbee.net> - 2012-10-21 09:34 +0100
Re: Programming style question Dr J R Stockton <reply1242@merlyn.demon.co.uk.invalid> - 2012-10-21 17:59 +0100
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-22 09:55 +0200
Re: Programming style question Tim Streater <timstreater@greenbee.net> - 2012-10-22 09:50 +0100
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-22 04:49 -0700
Re: Programming style question Tim Streater <timstreater@greenbee.net> - 2012-10-22 14:04 +0100
Re: Programming style question Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2012-10-22 16:07 +0200
Re: Programming style question Dr J R Stockton <reply1243@merlyn.demon.co.uk.invalid> - 2012-10-23 18:22 +0100
Re: Programming style question Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2012-10-22 16:01 +0200
Re: Programming style question Jim T. <x@y.z> - 2012-10-22 12:16 -0400
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-22 11:40 -0700
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-22 14:01 -0700
Re: Programming style question Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2012-10-23 10:07 +0200
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-23 09:43 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-23 11:49 +0200
Re: Programming style question Jim T. <x@y.z> - 2012-10-23 15:52 -0400
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-23 13:07 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-23 22:45 +0200
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-23 14:14 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-24 09:35 +0200
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-24 10:17 -0700
Re: Programming style question Dr J R Stockton <reply1243@merlyn.demon.co.uk.invalid> - 2012-10-25 18:41 +0100
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-25 17:03 -0700
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-25 20:14 -0700
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-25 20:46 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-26 09:55 +0200
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-26 06:18 -0700
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-26 17:43 +0200
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-26 09:57 -0700
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-26 10:24 -0700
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-26 14:18 -0700
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-27 10:45 +0200
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-27 12:58 +0200
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-27 16:18 +0200
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-27 18:08 +0200
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-27 18:26 +0200
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-27 19:43 +0200
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-27 21:09 +0200
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-27 22:53 +0200
Re: Programming style question John G Harris <john@nospam.demon.co.uk> - 2012-10-28 11:37 +0000
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-28 12:50 +0100
Re: Programming style question Martin Leese <please@see.Web.for.e-mail.INVALID> - 2012-10-28 13:43 -0600
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-28 23:58 +0100
Re: Programming style question John G Harris <john@nospam.demon.co.uk> - 2012-10-29 11:18 +0000
Re: Programming style question Eric Bednarz <bednarz@fahr-zur-hoelle.org> - 2012-10-27 23:58 +0200
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-28 12:43 +0100
Re: Programming style question Dr J R Stockton <reply1243@merlyn.demon.co.uk.invalid> - 2012-10-27 19:44 +0100
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-24 12:06 -0700
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-24 21:27 +0200
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-10-24 15:12 -0700
Re: Programming style question Tim Streater <timstreater@greenbee.net> - 2012-10-25 01:29 +0100
Re: Programming style question Stefan Weiss <krewecherl@gmail.com> - 2012-10-24 21:25 +0200
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-24 21:57 +0200
Re: Programming style question Stefan Weiss <krewecherl@gmail.com> - 2012-10-25 01:11 +0200
Re: Programming style question Christoph Becker <cmbecker69@gmx.de> - 2012-10-25 02:00 +0200
Re: Programming style question Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-24 20:27 -0700
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-25 08:44 +0200
Re: Programming style question Adam Silver <adambsilver@gmail.com> - 2012-10-25 04:28 -0700
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-25 23:18 +0200
Re: Programming style question Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-26 08:24 -0700
Re: Programming style question Stefan Weiss <krewecherl@gmail.com> - 2012-11-07 22:13 +0100
Re: Programming style question Tim Streater <timstreater@greenbee.net> - 2012-11-07 21:51 +0000
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-11-07 23:47 +0100
Re: Programming style question Stefan Weiss <krewecherl@gmail.com> - 2012-11-08 01:14 +0100
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-11-07 16:51 -0800
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-11-08 16:45 +0100
Re: Programming style question Scott Sauyet <scott.sauyet@gmail.com> - 2012-11-08 08:02 -0800
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-11-08 17:39 +0100
Re: Programming style question Gene Wirchenko <genew@ocis.net> - 2012-11-08 11:25 -0800
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-11-08 22:25 +0100
Re: Programming style question John G Harris <john@nospam.demon.co.uk> - 2012-11-09 10:19 +0000
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-11-09 17:41 +0100
Re: Programming style question Dr J R Stockton <reply1245@merlyn.demon.co.uk.invalid> - 2012-11-10 22:38 +0000
Re: Programming style question Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-22 12:32 -0700
Re: Programming style question Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2012-10-23 10:05 +0200
Re: Programming style question Christoph Becker <cmbecker69@gmx.de> - 2012-10-22 22:11 +0200
Re: Programming style question Stefan Weiss <krewecherl@gmail.com> - 2012-10-23 02:42 +0200
Re: Programming style question Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> - 2012-10-23 10:08 +0200
Re: Programming style question "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-20 18:34 +0200
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-18 11:57 +0200
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-18 13:06 +0100
Re: Programming style question "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2012-10-18 15:32 +0300
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-18 13:37 +0100
Re: Programming style question "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2012-10-18 15:55 +0300
Re: Programming style question John G Harris <john@nospam.demon.co.uk> - 2012-10-19 10:12 +0100
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-19 07:24 -0700
Re: Programming style question John G Harris <john@nospam.demon.co.uk> - 2012-10-20 17:47 +0100
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-24 01:15 +0100
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-24 01:31 +0100
Re: Programming style question "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2012-10-24 07:34 +0300
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-24 19:57 +0200
Re: Programming style question "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2012-10-24 21:02 +0300
Re: Programming style question Patricia Shanahan <pats@acm.org> - 2012-10-18 20:15 -0700
Re: Programming style question Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-24 01:21 +0100
Re: Programming style question Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-21 17:57 -0700
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