It makes reordering easier, editing the list less error-prone, and generating

Javascript from data a little simpler.  Overall, probably a good thing.



M.









________________________________

From: Simon Kenyon Shepard <simon.shepard@...>

To: jslint_com@yahoogroups.com

Sent: Wed, April 7, 2010 5:26:29 AM

Subject: Re: [jslint] Re: option.es5



So, would I be correct in surmising that this change from ES3 to ES5 to

allow the trailing comma is for developer convenience as in the

aforementioned reordering example?



Out of curiosity are there any other reasons or examples where this would

come in useful?







On 6 April 2010 21:48, Michael Lorton <mlorton@...> wrote:



>

>

> > ES3 does not allow the trailing comma, so IE is correct when it rejects

> it.

>

> Distinguo: ES3 does not allow the trailing comma, so Internet Explorer is

> correct TO reject

> it.

>

> IE does the right thing the wrong way. It rejects the comma and gives an

> ambiguous message and the line number BUT NOT THE FILE NAME.

>

> Even assuming Microsoft employees should otherwise be allowed to live, this

> transgression (perversely maintained through every version of IE) is alone

> grounds for hunting them all down with dogs and shotguns.

>

> M.

>

> ________________________________

> From: Douglas Crockford <douglas@... <douglas%40crockford.com>>

>

> To: jslint_com@yahoogroups.com <jslint_com%40yahoogroups.com>

> Sent: Tue, April 6, 2010 12:35:27 PM

>

> Subject: [jslint] Re: option.es5

>

> --- In jslint_com@yahoogroups.com <jslint_com%40yahoogroups.com>, Rob

> Richardson <erobrich@...> wrote:

> >

> > I can see in certain circumstances that trailing commas could be deemed

> acceptable, though I'm still of the mindset that this is bad form in most

> JavaScript contexts. I'm failing to see how opting into this practice is

> linked to ES5 compatibility though. Does ES5 specifically dictate that

> trailing commas are acceptable?

>

> ES3 does not allow the trailing comma, so IE is correct when it rejects it.

>

> ES5 allows but does not require the trailing comma.

>

> There is often confusion between separators and terminators. Commas are

> separators. Semicolons are terminators.

>

> ------------------------------------

>

> Yahoo! Groups Links

>

>

> [Non-text portions of this message have been removed]

>

>

>







--

"We are the music makers, And we are the dreamers of dreams"





[Non-text portions of this message have been removed]







------------------------------------



Yahoo! Groups Links







[Non-text portions of this message have been removed]

So, would I be correct in surmising that this change from ES3 to ES5 to

allow the trailing comma is for developer convenience as in the

aforementioned reordering example?



Out of curiosity are there any other reasons or examples where this would

come in useful?







On 6 April 2010 21:48, Michael Lorton <mlorton@...> wrote:



>

>

> > ES3 does not allow the trailing comma, so IE is correct when it rejects

> it.

>

> Distinguo: ES3 does not allow the trailing comma, so Internet Explorer is

> correct TO reject

> it.

>

> IE does the right thing the wrong way. It rejects the comma and gives an

> ambiguous message and the line number BUT NOT THE FILE NAME.

>

> Even assuming Microsoft employees should otherwise be allowed to live, this

> transgression (perversely maintained through every version of IE) is alone

> grounds for hunting them all down with dogs and shotguns.

>

> M.

>

> ________________________________

> From: Douglas Crockford <douglas@... <douglas%40crockford.com>>

>

> To: jslint_com@yahoogroups.com <jslint_com%40yahoogroups.com>

> Sent: Tue, April 6, 2010 12:35:27 PM

>

> Subject: [jslint] Re: option.es5

>

> --- In jslint_com@yahoogroups.com <jslint_com%40yahoogroups.com>, Rob

> Richardson <erobrich@...> wrote:

> >

> > I can see in certain circumstances that trailing commas could be deemed

> acceptable, though I'm still of the mindset that this is bad form in most

> JavaScript contexts. I'm failing to see how opting into this practice is

> linked to ES5 compatibility though. Does ES5 specifically dictate that

> trailing commas are acceptable?

>

> ES3 does not allow the trailing comma, so IE is correct when it rejects it.

>

> ES5 allows but does not require the trailing comma.

>

> There is often confusion between separators and terminators. Commas are

> separators. Semicolons are terminators.

>

> ------------------------------------

>

> Yahoo! Groups Links

>

>

> [Non-text portions of this message have been removed]

>

>

>







--

"We are the music makers, And we are the dreamers of dreams"





[Non-text portions of this message have been removed]

--- In jslint_com@yahoogroups.com, Michael Lorton <mlorton@...> wrote:

> Even assuming Microsoft employees should otherwise be allowed to live, this

transgression (perversely maintained through every version of IE) is alone

grounds for hunting them all down with dogs and shotguns.





You are way out of line. Tone it down.

>  ES3 does not allow the trailing comma, so IE is correct when it rejects

it.



Distinguo: ES3 does not allow the trailing comma, so Internet Explorer is

correct TO reject

it.



IE does the right thing the wrong way.  It rejects the comma and gives an

ambiguous message and the line number BUT NOT THE FILE NAME.



Even assuming Microsoft employees should otherwise be allowed to live, this

transgression (perversely maintained through every version of IE) is alone

grounds for hunting them all down with dogs and shotguns.



M.









________________________________

From: Douglas Crockford <douglas@...>

To: jslint_com@yahoogroups.com

Sent: Tue, April 6, 2010 12:35:27 PM

Subject: [jslint] Re: option.es5



--- In jslint_com@yahoogroups.com, Rob Richardson <erobrich@...> wrote:

>

> I can see in certain circumstances that trailing commas could be deemed

acceptable, though I'm still of the mindset that this is bad form in most

JavaScript contexts.  I'm failing to see how opting into this practice is linked

to ES5 compatibility though.  Does ES5 specifically dictate that trailing commas

are acceptable?



ES3 does not allow the trailing comma, so IE is correct when it rejects it.



ES5 allows but does not require the trailing comma.



There is often confusion between separators and terminators. Commas are

separators. Semicolons are terminators.







------------------------------------



Yahoo! Groups Links







[Non-text portions of this message have been removed]

--- In jslint_com@yahoogroups.com, Rob Richardson <erobrich@...> wrote:

>

> I can see in certain circumstances that trailing commas could be deemed

acceptable, though I'm still of the mindset that this is bad form in most

JavaScript contexts.  I'm failing to see how opting into this practice is linked

to ES5 compatibility though.  Does ES5 specifically dictate that trailing commas

are acceptable?



ES3 does not allow the trailing comma, so IE is correct when it rejects it.



ES5 allows but does not require the trailing comma.



There is often confusion between separators and terminators. Commas are

separators. Semicolons are terminators.

I can see in certain circumstances that trailing commas could be deemed

acceptable, though I'm still of the mindset that this is bad form in most

JavaScript contexts.  I'm failing to see how opting into this practice is linked

to ES5 compatibility though.  Does ES5 specifically dictate that trailing commas

are acceptable?



Rob











________________________________

From: Michael Mikowski <z_mikowski@...>

To: jslint_com@yahoogroups.com

Sent: Tue, April 6, 2010 11:56:46 AM

Subject: Re: [jslint] Re: option.es5





Whoops.  Need more coffee.  Should be var hash_example = {...}, not [].   But

you get the idea.



____________ _________ _________ __

From: Michael Mikowski <z_mikowski@yahoo. com>

To: jslint_com@yahoogro ups.com

Sent: Tue, April 6, 2010 11:54:25 AM

Subject: Re: [jslint] Re: option.es5



There is a very good reason to allow for trailing commas (even though IE js

doesn't) -- Consider this 'object' (since we only use it as an associative array

here, we call it a hash):



var hash_example = [

foo   : 'bar',

zing  : 'zang',

one   : 'two'

];



Now lets say I want to reorder the keys so they are alphabetical:



var hash_example = [

foo   : 'bar',

one   : 'two'

zing  : 'zang',

];



Boom.  Instant error -- in two places.  Allowing trailing commas avoids this

problem nicely.



In Perl, a trailing comma is best practice, and omitting the trailing comma is

considered sloppy.



If IE would allow trailing commas, I'd use them consistently.  Since it doesn't,

I use jslint to find the above errors :)



Cheers, Mike



____________ _________ _________ __

From: boyopeg <boyopeg@gmail. com>

To: jslint_com@yahoogro ups.com

Sent: Tue, April 6, 2010 9:47:41 AM

Subject: [jslint] Re: option.es5



It seems to me that the trailing comma in object notation is a rather bad coding

practice. I'm fine with JS parsers being able to ignore errors such as these.

But why should a style and syntax checking tool like JSLint be blind to such

sloppy code practices?  Am I missing something with this option?



-noah



--- In jslint_com@yahoogro ups.com, "Douglas Crockford" <douglas@... > wrote:

>

> --- In jslint_com@yahoogro ups.com, "Douglas Crockford" <douglas@> wrote:

> >

> > There is a new option, Tolerate ES5 syntax. If you check this option, JSLint

will accept the new get/set syntax in object literals.

> >

> > It will require that the get and set functions be declared together, that

the get function have no parameters, and that the set function will have a

single parameter called 'value'.

> >

> > Please let me know if you find any problems.

>

>

> option.es5 will now relax the reserved word restriction on object

> literals and dot notation, and tolerate a dangling comma, so

>

>     var object = {

>         class: x.class,

>     };

>

> is accepted.











[Non-text portions of this message have been removed]

Whoops.  Need more coffee.  Should be var hash_example = {...}, not [].   But

you get the idea.











________________________________

From: Michael Mikowski <z_mikowski@...>

To: jslint_com@yahoogroups.com

Sent: Tue, April 6, 2010 11:54:25 AM

Subject: Re: [jslint] Re: option.es5





There is a very good reason to allow for trailing commas (even though IE js

doesn't) -- Consider this 'object' (since we only use it as an associative array

here, we call it a hash):



var hash_example = [

   foo   : 'bar',

   zing  : 'zang',

   one   : 'two'

];



Now lets say I want to reorder the keys so they are alphabetical:



var hash_example = [

   foo   : 'bar',

   one   : 'two'

   zing  : 'zang',

];



Boom.  Instant error -- in two places.  Allowing trailing commas avoids this

problem nicely.



In Perl, a trailing comma is best practice, and omitting the trailing comma is

considered sloppy.



If IE would allow trailing commas, I'd use them consistently.  Since it doesn't,

I use jslint to find the above errors :)







Cheers, Mike







________________________________

From: boyopeg <boyopeg@...>

To: jslint_com@yahoogroups.com

Sent: Tue, April 6, 2010 9:47:41 AM

Subject: [jslint] Re: option.es5





It seems to me that the trailing comma in object notation is a rather bad coding

practice. I'm fine with JS parsers being able to ignore errors such as these.

But why should a style and syntax checking tool like JSLint be blind to such

sloppy code practices?  Am I missing something with this option?



-noah



--- In jslint_com@yahoogro ups.com, "Douglas Crockford" <douglas@... > wrote:

>

> --- In jslint_com@yahoogro ups.com, "Douglas Crockford" <douglas@> wrote:

> >

> > There is a new option, Tolerate ES5 syntax. If you check this option, JSLint

will accept the new get/set syntax in object literals.

> >

> > It will require that the get and set functions be declared together, that

the get function have no parameters, and that the set function will have a

single parameter called 'value'.

> >

> > Please let me know if you find any problems.

>

>

> option.es5 will now relax the reserved word restriction on object

> literals and dot notation, and tolerate a dangling comma, so

>

>     var object = {

>         class: x.class,

>     };

>

> is accepted.

>









[Non-text portions of this message have been removed]

There is a very good reason to allow for trailing commas (even though IE js

doesn't) -- Consider this 'object' (since we only use it as an associative array

here, we call it a hash):



var hash_example = [

   foo   : 'bar',

   zing  : 'zang',

   one   : 'two'

];



Now lets say I want to reorder the keys so they are alphabetical:



var hash_example = [

   foo   : 'bar',

   one   : 'two'

   zing  : 'zang',

];



Boom.  Instant error -- in two places.  Allowing trailing commas avoids this

problem nicely.



In Perl, a trailing comma is best practice, and omitting the trailing comma is

considered sloppy.



If IE would allow trailing commas, I'd use them consistently.  Since it doesn't,

I use jslint to find the above errors :)







Cheers, Mike







________________________________

From: boyopeg <boyopeg@...>

To: jslint_com@yahoogroups.com

Sent: Tue, April 6, 2010 9:47:41 AM

Subject: [jslint] Re: option.es5





It seems to me that the trailing comma in object notation is a rather bad coding

practice. I'm fine with JS parsers being able to ignore errors such as these.

But why should a style and syntax checking tool like JSLint be blind to such

sloppy code practices?  Am I missing something with this option?



-noah



--- In jslint_com@yahoogro ups.com, "Douglas Crockford" <douglas@... > wrote:

>

> --- In jslint_com@yahoogro ups.com, "Douglas Crockford" <douglas@> wrote:

> >

> > There is a new option, Tolerate ES5 syntax. If you check this option, JSLint

will accept the new get/set syntax in object literals.

> >

> > It will require that the get and set functions be declared together, that

the get function have no parameters, and that the set function will have a

single parameter called 'value'.

> >

> > Please let me know if you find any problems.

>

>

> option.es5 will now relax the reserved word restriction on object

> literals and dot notation, and tolerate a dangling comma, so

>

>     var object = {

>         class: x.class,

>     };

>

> is accepted.

>









[Non-text portions of this message have been removed]

It seems to me that the trailing comma in object notation is a rather bad coding

practice. I'm fine with JS parsers being able to ignore errors such as these.

But why should a style and syntax checking tool like JSLint be blind to such

sloppy code practices?  Am I missing something with this option? 



-noah



--- In jslint_com@yahoogroups.com, "Douglas Crockford" <douglas@...> wrote:

>

> --- In jslint_com@yahoogroups.com, "Douglas Crockford" <douglas@> wrote:

> >

> > There is a new option, Tolerate ES5 syntax. If you check this option, JSLint

will accept the new get/set syntax in object literals.

> >

> > It will require that the get and set functions be declared together, that

the get function have no parameters, and that the set function will have a

single parameter called 'value'.

> >

> > Please let me know if you find any problems.

>

>

> option.es5 will now relax the reserved word restriction on object

> literals and dot notation, and tolerate a dangling comma, so

>

>     var object = {

>         class: x.class,

>     };

>

> is accepted.

>

--- In jslint_com@yahoogroups.com, "Douglas Crockford" <douglas@...> wrote:

>

> There is a new option, Tolerate ES5 syntax. If you check this option, JSLint

will accept the new get/set syntax in object literals.

>

> It will require that the get and set functions be declared together, that the

get function have no parameters, and that the set function will have a single

parameter called 'value'.

>

> Please let me know if you find any problems.





option.es5 will now relax the reserved word restriction on object

literals and dot notation, and tolerate a dangling comma, so



     var object = {

         class: x.class,

     };



is accepted.

The Widget Tester Widget (version 8.9) with JSLint Edition 2010-04-05 is now at



http://tinyurl.com/5unocx    .



This version has the new "Tolerate ES5 syntax" option.



Harry.

There is a new option, Tolerate ES5 syntax. If you check this option, JSLint

will accept the new get/set syntax in object literals.



It will require that the get and set functions be declared together, that the

get function have no parameters, and that the set function will have a single

parameter called 'value'.



Please let me know if you find any problems. Eventually it may recognize other

corrections with this option, such as dangling commas in array and object

literals.