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Insert Function into Error Object

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  Insert Function into Error Object MC <news@aisus.com> - 2013-12-25 20:48 -0600
    Re: Insert Function into Error Object Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2013-12-26 18:46 -0200
      Re: Insert Function into Error Object MC <news@aisus.com> - 2013-12-26 18:47 -0600
        Re: Insert Function into Error Object "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2013-12-27 09:54 +0100
          Re: Insert Function into Error Object MC <news@aisus.com> - 2013-12-27 10:16 -0600
          Re: Insert Function into Error Object MC <news@aisus.com> - 2013-12-27 10:26 -0600
        Re: Insert Function into Error Object JJ <duh@nah.meh> - 2013-12-28 00:53 +0700
    Re: Insert Function into Error Object "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2013-12-26 20:17 -0800
      Re: Insert Function into Error Object Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2013-12-27 11:15 -0200
        Re: Insert Function into Error Object MC <news@aisus.com> - 2013-12-27 10:09 -0600
      Re: Insert Function into Error Object Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-12-27 17:24 +0100
        Re: Insert Function into Error Object MC <news@aisus.com> - 2013-12-27 10:34 -0600
          Re: Insert Function into Error Object "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2013-12-27 17:57 +0100
    Re: Insert Function into Error Object MC <news@aisus.com> - 2013-12-28 10:20 -0600
      Re: Insert Function into Error Object JJ <duh@nah.meh> - 2013-12-29 07:12 +0700
      Re: Insert Function into Error Object Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2013-12-29 20:13 +0100
        Re: Insert Function into Error Object Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-12-29 20:31 +0100
    Re: Insert Function into Error Object MC <news@aisus.com> - 2014-01-12 11:26 -0600
      Re: Insert Function into Error Object "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-01-13 02:59 -0800
        Re: Insert Function into Error Object Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-01-13 12:59 +0100
          Re: Insert Function into Error Object "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-01-13 04:37 -0800

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#22408 — Insert Function into Error Object

FYI, I have researched, tried, and failed.
I am trying to extend the Error object in such fashion that upon being 
created by a js error, my function is called. I already know I can do 
window.onError(), but I need to insert my own function into the Error 
object if that is possible.

function myErrorCall(e) {
    // do something	
}

Also, I do not want to extend the Error object and throw myError objects.

Thank you!

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#22416

Em 26/12/2013 00:48, MC escreveu:
>
>
> FYI, I have researched, tried, and failed.
> I am trying to extend the Error object in such fashion that upon being
> created by a js error, my function is called. I already know I can do
> window.onError(), but I need to insert my own function into the Error
> object if that is possible.
>
> function myErrorCall(e) {
>     // do something
> }
>
> Also, I do not want to extend the Error object and throw myError objects.
>

A hint from "The Definitive Guide", 4th Edition:

<http://docstore.mik.ua/orelly/webprog/jscript/ch13_05.htm>


-- 
Joao Rodrigues (J.R.)

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#22418

That refers to the onError method, which I already know about and does 
not modify the Error object.

Thank you for posting!

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#22421

MC <news@aisus.com> wrote on 27 dec 2013 in comp.lang.javascript:

> That refers to the onError method, which I already know about and does 
> not modify the Error object.

What is "that"?

This is Usenet, not an email, so please quote what you are responding on.

-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#22431

On 12/27/2013 2:54 AM, Evertjan. wrote:
> MC <news@aisus.com> wrote on 27 dec 2013 in comp.lang.javascript:
>
>> That refers to the onError method, which I already know about and does
>> not modify the Error object.
>
> What is "that"?
>
> This is Usenet, not an email, so please quote what you are responding on.
>

Evertjan...cranky...Happy Holidays!!!! :-) So I did...better ;-)

Do you have any input? I need to insert a function to be called inside 
the Error object, as part of the Error process.

Where is David Mark and our other illustrious group members? David and 
you were always particularily insightful.

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#22433

On 12/27/2013 2:54 AM, Evertjan. wrote:
> MC <news@aisus.com> wrote on 27 dec 2013 in comp.lang.javascript:
>
>> That refers to the onError method, which I already know about and does
>> not modify the Error object.
>
> What is "that"?
>
> This is Usenet, not an email, so please quote what you are responding on.
>


Evertjan...cranky...Happy Holidays!!!! :-) So I did include what I was 
responding to...better ;-)

Do you have any input? I need to insert a function to be called inside 
the Error object, as part of the Error process.

Where is David Mark and our other illustrious group members? David and 
you were always particularily insightful.

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#22437

On Thu, 26 Dec 2013 18:47:07 -0600, MC wrote:
> That refers to the onError method, which I already know about and does 
> not modify the Error object.
> 
> Thank you for posting!

What you want shouldn't be allowed. It can crash the interpreter.

You can replace the Error object constructor, but the interpreter use its
own reference to the original Error object constructor when generating an
exception.

If the Error object is allowed to be replaced, then code like this would be
catastrophic.

function myError(){
  var a = undefinedVariable;
  a = a.value; //BAM! Infinite loop.
}
window.Error = myError;
var a = undefinedVariable;
a = a.value; //BAM!

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#22422

On Wednesday, December 25, 2013 8:48:48 PM UTC-6, MC wrote:

> Also, I do not want to extend the Error object and throw myError objects.

Why not?

Another alternative is to shadow the Error object.

Depending on the target platform, you could use a proxy as well:

<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy>

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#22423

On Fri 27/12/2013 02:17, Michael Haufe (TNO) wrote:
> On Wednesday, December 25, 2013 8:48:48 PM UTC-6, MC wrote:
>
>> Also, I do not want to extend the Error object and throw myError objects.
>
> Why not?

Yes, it is possible to extend the Error.prototype, by adding the OP's 
function as a method:
<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/prototype>


-- 
Joao Rodrigues (J.R.)

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#22429

On 12/27/2013 7:15 AM, Joao Rodrigues wrote:
> On Fri 27/12/2013 02:17, Michael Haufe (TNO) wrote:
>> On Wednesday, December 25, 2013 8:48:48 PM UTC-6, MC wrote:
>>
>>> Also, I do not want to extend the Error object and throw myError
>>> objects.
>>
>> Why not?
>
> Yes, it is possible to extend the Error.prototype, by adding the OP's
> function as a method:
> <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/prototype>
>
>
>

Because it is not in the project spec. I am not allowed to create a new 
extended myError object. I need to add the functionality to the Error 
object.

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#22432

Michael Haufe (TNO) wrote:

> On Wednesday, December 25, 2013 8:48:48 PM UTC-6, MC wrote:
>> Also, I do not want to extend the Error object and throw myError objects.
> 
> Why not?

Depends on what is meant by that.  Inheriting from Error.prototype and 
calling Error from a user-defined constructor at least works well in JSX:

<http://PointedEars.de/wsvn/JSX/trunk/object.js>
 
> Another alternative is to shadow the Error object.

Meaning?
 
-- 
PointedEars

Twitter: @PointedEars2
Please do not Cc: me. / Bitte keine Kopien per E-Mail.

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#22434

On 12/27/2013 10:24 AM, Thomas 'PointedEars' Lahn wrote:
> Michael Haufe (TNO) wrote:
>
>> On Wednesday, December 25, 2013 8:48:48 PM UTC-6, MC wrote:
>>> Also, I do not want to extend the Error object and throw myError objects.
>>
>> Why not?
>
> Depends on what is meant by that.  Inheriting from Error.prototype and
> calling Error from a user-defined constructor at least works well in JSX:
>
> <http://PointedEars.de/wsvn/JSX/trunk/object.js>
>
>> Another alternative is to shadow the Error object.
>
> Meaning?
>
>

I second that...what is shadowing the Error object?

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#22435

MC <news@aisus.com> wrote on 27 dec 2013 in comp.lang.javascript:

> On 12/27/2013 10:24 AM, Thomas 'PointedEars' Lahn wrote:
>> Michael Haufe (TNO) wrote:
>>
>>> On Wednesday, December 25, 2013 8:48:48 PM UTC-6, MC wrote:
>>>> Also, I do not want to extend the Error object and throw myError
>>>> objects. 
>>>
>>> Why not?
>>
>> Depends on what is meant by that.  Inheriting from Error.prototype and
>> calling Error from a user-defined constructor at least works well in
>> JSX: 
>>
>> <http://PointedEars.de/wsvn/JSX/trunk/object.js>
>>
>>> Another alternative is to shadow the Error object.
>>
>> Meaning?

> I second that...what is shadowing the Error object?
 
Stealthily following such object by private eyes?



-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#22449

On 12/25/2013 8:48 PM, MC wrote:
>
>
> FYI, I have researched, tried, and failed.
> I am trying to extend the Error object in such fashion that upon being
> created by a js error, my function is called. I already know I can do
> window.onError(), but I need to insert my own function into the Error
> object if that is possible.
>
> function myErrorCall(e) {
>     // do something
> }
>
> Also, I do not want to extend the Error object and throw myError objects.
>
> Thank you!

So no one has any ideas on how to attach a function to be called when 
the Error object is called?

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#22462

On Sat, 28 Dec 2013 10:20:48 -0600, MC wrote:
> On 12/25/2013 8:48 PM, MC wrote:
>>
>>
>> FYI, I have researched, tried, and failed.
>> I am trying to extend the Error object in such fashion that upon being
>> created by a js error, my function is called. I already know I can do
>> window.onError(), but I need to insert my own function into the Error
>> object if that is possible.
>>
>> function myErrorCall(e) {
>>     // do something
>> }
>>
>> Also, I do not want to extend the Error object and throw myError objects.
>>
>> Thank you!
> 
> So no one has any ideas on how to attach a function to be called when 
> the Error object is called?

It shouldn't be allowed. It can cause infinite exception and stack overflow
if the Error constructor causes an exception.

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#22478

2013-12-28 17:20, MC wrote:
[...]

> So no one has any ideas on how to attach a function to be called when
> the Error object is called?
>

Take a look at: 
http://stackoverflow.com/questions/783818/how-do-i-create-a-custom-error-in-javascript

-- 
Cezary Tomczyk
http://www.ctomczyk.pl/

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#22480

Cezary Tomczyk wrote:

> 2013-12-28 17:20, MC wrote:
> [...]
>> So no one has any ideas on how to attach a function to be called when
>> the Error object is called?
> 
> Take a look at:
> http://stackoverflow.com/questions/783818/how-do-i-create-a-custom-error-in-javascript

The accepted answer is wrong as explained many times, not least in

<http://stackoverflow.com/a/12593269/855543>

The correct approach is

  NotImplementedError.prototype = (function () {
    function Foo () {}
    Foo.prototype = Error.prototype;
    return new Foo;
  }());

or simply

  NotImplementedError.prototype = Object.create(Error.prototype, {
    …
  });

See also JSX:object.js.

-- 
PointedEars

Twitter: @PointedEars2
Please do not Cc: me. / Bitte keine Kopien per E-Mail.

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#22583

On 12/25/2013 8:48 PM, MC wrote:
>
>
> FYI, I have researched, tried, and failed.
> I am trying to extend the Error object in such fashion that upon being
> created by a js error, my function is called. I already know I can do
> window.onError(), but I need to insert my own function into the Error
> object if that is possible.
>
> function myErrorCall(e) {
>     // do something
> }
>
> Also, I do not want to extend the Error object and throw myError objects.
>
> Thank you!

I guess no one knows how to insert a function into the Error object or 
add an event listener to it. All the suggestions have been to do 
something else.

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#22593

On Sunday, January 12, 2014 11:26:58 AM UTC-6, MC wrote:

> I guess no one knows how to insert a function into the Error object or 
> add an event listener to it. All the suggestions have been to do 
> something else.

Use a proxy

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#22594

Michael Haufe (TNO) wrote:

> On Sunday, January 12, 2014 11:26:58 AM UTC-6, MC wrote: 
>> I guess no one knows how to insert a function into the Error object or
>> add an event listener to it. All the suggestions have been to do
>> something else.
> 
> Use a proxy

How would this “insert a function into the Error object” or “add an event 
listener to the Error object”?  ISTM the OP either does not know what an 
event listener is, or that events have to do with the DOM, not the core 
language.  Indeed, they are not clear at all on what they intend to do and 
why they think it is necessary in the first place.

This is not a guessing game.

-- 
PointedEars

Twitter: @PointedEars2
Please do not Cc: me. / Bitte keine Kopien per E-Mail.

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