domenic at domenicdenicola.com (2014-02-10T22:36:37.677Z)
although, despite being advocated differently in every book/example out
there, many developers do this:
```js
Whatever.prototype = {
method: function(){},
property: 123
};
```
forgetting to redefine the constructor property that will also be
enumerable at that time if re-addressed.
TL;DR obj.constructor.name is not reliable with non ES6 code, usually
totally unreliable with old libraries producing always the string `Object`
as result
Cheers
P.S. that check is pointless regardless, since your `constructor.name`
might be inside a namespace you won't be able to address ... stick with
constructors and `instanceof` you know, don't try to use `constructor.name`
for any sort of magic in production ... just saying
although, despite being advocated differently in every book/example out there, many developers do this: Whatever.prototype = { method: function(){}, property: 123 }; forgetting to redefine the constructor property that will also be enumerable at that time if re-addressed. TL;DR obj.constructor.name is not reliable with non ES6 code, usually totally unreliable with old libraries producing always the string `Object` as result Cheers P.S. that check is pointless regardless, since your `constructor.name` might be inside a namespace you won't be able to address ... stick with constructors and `instanceof` you know, don't try to use `constructor.name` for any sort of magic in production ... just saying On Fri, Feb 7, 2014 at 8:27 PM, Timothy Quinn <tim.c.quinn at gmail.com> wrote: > Sweet. Thanks for the quick responses =D > > > On Fri, Feb 7, 2014 at 11:24 PM, Erik Arvidsson <erik.arvidsson at gmail.com>wrote: > >> Function name is in the latest ES6 draft. >> >> On Fri Feb 07 2014 at 11:15:31 PM, Timothy Quinn <tim.c.quinn at gmail.com> >> wrote: >> >>> Digging into ECMA-262, I cannot find this noted but it appears to be >>> implemented in V8 and SpiderMonkey. >>> >>> Mozilla states this as non-standard<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/name>so I am guessing that its not documented in ECMA-262. >>> >>> Is this defined in the specification or did I miss it? If not, +1 on its >>> standardization into the specification. >>> >>> - Tim >>> >>> >>> On Fri, Feb 7, 2014 at 10:52 PM, Timothy Quinn <tim.c.quinn at gmail.com>wrote: >>> >>> LOL. I did not realize that was implemented already :) >>> >>> Thanks, >>> - Tim >>> >>> >>> On Fri, Feb 7, 2014 at 10:28 PM, Domenic Denicola < >>> domenic at domenicdenicola.com> wrote: >>> >>> o.constructor.name seems good? >>> ------------------------------ >>> From: Timothy Quinn <tim.c.quinn at gmail.com> >>> Sent: 2/7/2014 22:26 >>> To: es-discuss at mozilla.org >>> Subject: Efficient determination of implemented class name >>> >>> An area of challenge in JavaScript is the ability to detect a >>> JavaScript objects implemented class name. I have done this in the past >>> with some success by parsing the objects constructor but I know that this >>> depends on the Object constructor being named and is not very efficient as >>> it requires the processing of a large string. >>> >>> Is it possible to include into the ECMA Specification a method of >>> Object that returns the constructor function name which can be subsequently >>> be used as an efficient class name detection mechanism? Maybe >>> <Object>.getFunctionName(). >>> >>> My current current slow but steady method for detecting classes is as >>> follows: >>> >>> function objClassName(o){ >>> if(o===undefined){return "(undefined)" } >>> if(o===null){return "(null)" } >>> var a=/function\s+(.+)\s*\(.*\)\s*\{/.exec(o.constructor) >>> return (a && a[1] ? a[1] : "(unknown)") >>> }; >>> >>> Thanks! >>> Tim >>> >>> >>> >>> > > _______________________________________________ > es-discuss mailing list > es-discuss at mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20140207/b5eaf93c/attachment.html>