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From: David Mark on 26 Jul 2010 21:06
On Jul 26, 4:18 pm, Ry Nohryb <jo...(a)jorgechamorro.com> wrote:
> On Jul 26, 2:26 pm, Stanimir Stamenkov <s7a...(a)netscape.net> wrote:
>
>
>
>
>
> > As the number of utility functions I write increases I've started to
> > use a global variable acting as namespace for my functions.  Given
> > my functions are spread in couple of .js files and the order of
> > loading is not significant (documents may include random combination
> > of the files) I've wondered how it is best to initialize the
> > namespace object.
>
> > I generally use the following construct in my .js files:
>
> > (function () {
> >      if (typeof MYNS === "undefined") {
> >          MYNS = { };
> >      }
> >      // Add stuff to MYNS...
>
> > }());
>
> > But then running this through JSLint tells me: "'MYNS' is not
> > defined".  Changing the code to:
>
> > (function () {
> >      if (typeof this.MYNS === "undefined") {
> >          this.MYNS = { };
> >      }
> >      // Add stuff to MYNS...
>
> > }());
>
> > results in no JSLint errors but then it lists 'MYNS' as member and
> > not a global variable, if it matters at all.  Which of the both
> > forms is recommended?  Should I just tell JSLint 'MYNS' is a
> > predefined global?
>
> Use window.MYNS instead of this.MYNS, and, in order to avoid
> overwriting/destroying a possibly pre-existing/previously-defined
> MYNS :
>
> window.MYNS= window.MYNS || {};

You've finally lost it, haven't you Jorge?

var MYNS;

if (!MYNS) {
MYNS = {};
}

Or:-

var MYNS;

MYNS = MYNS || {};


>
> JSLint then won't complain because global vars are properties of the
> global object, and the 'window' and 'self' globals are references to
> the Global Object itself:

Not that it matters a whit, but last I checked, JSLint decried the use
of - window - as an "implied global". (!)

>
> GlobalObject.window === GlobalObject.self === GlobalObject ===
> (function(){return this})()

As you've been told a thousand times, that proves nothing.

>
> and thus window.someGlobalVarName is only an explicit way of saying
> "hey, this is a global var !".

Get better Jorge!
From: David Mark on 26 Jul 2010 21:08
On Jul 26, 3:47 pm, Asen Bozhilov <asen.bozhi...(a)gmail.com> wrote:
> Stanimir Stamenkov wrote:
> > results in no JSLint errors but then it lists 'MYNS' as member and
> > not a global variable, if it matters at all.  Which of the both
> > forms is recommended?  Should I just tell JSLint 'MYNS' is a
> > predefined global?
>
> Both are not good. First, because use undeclared assignment. In the
> second approach the problem is in ES5 environment. The `this'
> associated with that execution context in strict mode must be
> `undefined'. So you will get TypeError.

I don't see the strict mode problem to be an issue as you would have
to explicitly require strict mode in the code.
From: David Mark on 26 Jul 2010 21:15
On Jul 26, 8:06 pm, Ry Nohryb <jo...(a)jorgechamorro.com> wrote:
> On Jul 27, 1:49 am, Ry Nohryb <jo...(a)jorgechamorro.com> wrote:
>
>
>
> > But it (JSLint) will probably complain about the use of an undeclared
> > MYNS because it's being used prior to its declaration.
>
> Well, I mean, at that point it's -probably- undefined, but not
> undeclared.

You know, for somebody who decries the "decline" of this newsgroup,
you should know that waffling over such a simple question/answer is
not helping matters at all. ;)
From: David Mark on 26 Jul 2010 21:20
On Jul 26, 8:57 pm, RobG <rg...(a)iinet.net.au> wrote:
> On Jul 26, 10:26 pm, Stanimir Stamenkov <s7a...(a)netscape.net> wrote:
>
> > As the number of utility functions I write increases I've started to
> > use a global variable acting as namespace for my functions.  Given
> > my functions are spread in couple of .js files and the order of
> > loading is not significant (documents may include random combination
> > of the files) I've wondered how it is best to initialize the
> > namespace object.
>
> > I generally use the following construct in my .js files:
>
> > (function () {
> >      if (typeof MYNS === "undefined") {
> >          MYNS = { };
>
> Don't be coy about creating global variables. If you want to create
> one, declare it right up front. Just before the anonymous function,
> use:
>
>   var MYNS;
>
> Note that if MYNS already exists, the extra variable declaration has
> no impact, so it is absolutely safe. Anyone reading your code will see
> it right at the top and know it's yours.
>
> >      }
> >      // Add stuff to MYNS...
>
> > }());
>
> > But then running this through JSLint tells me: "'MYNS' is not
> > defined".  Changing the code to:
>
> > (function () {
> >      if (typeof this.MYNS === "undefined") {
> >          this.MYNS = { };
> >      }
> >      // Add stuff to MYNS...
>
> Just declare it before the function.
>
> > }());
>
> > results in no JSLint errors but then it lists 'MYNS' as member and
> > not a global variable, if it matters at all.  Which of the both
> > forms is recommended?  Should I just tell JSLint 'MYNS' is a
> > predefined global?
>
> If you want MYNS to be a native Object object, then you should test
> explicitly for that. If you want to be strict, then the following
> should run as global code:
>
>   var MYNS;
>   if (typeof MYNS != 'object') {
>     MYNS = {};
>   }

Forgot the check for null:-

var MYNS;
if (!MYNS || typeof MYNS != 'object') {
  MYNS = {};
}

>
> Now you know excatly what MYNS is (and may have stomped on someone
> else's MYNS, but that's for the user of your code to fix).
>
> Don't fall for junk like the following (which is in a commercial
> product in wide use where I work):
>
>   if (dwr == null) var dwr = {};

Dojo-esque. :( You know they un-declared all of their globals about
a year ago because somebody suggested it would be "faster". :)

>
> Which infers that variables can be conditionally decalred (they can't)
> and depends on the truthiness of undefined == null. The author
> probably should have written:
>
>   var dwr;
>   if (typeof dwr == 'undefined') {
>     dwr = {};
>   }

Or just used boolean type conversion as any "falsey" value is going to
be undesirable.

var dwr;

if (!dwr) {
dwr = {};
}

>
> Anyhow, it is probably sufficient to use the following as global code:
>
>   var MYNS = MYNS || {};
>

That will work as well. I don't particularly care for it, but that's
a matter of personal taste.
From: Scott Sauyet on 26 Jul 2010 21:32
David Mark wrote:
> On Jul 26, 8:57 pm, RobG <rg...(a)iinet.net.au> wrote:
>> Anyhow, it is probably sufficient to use the following as global code:
>
>>   var MYNS = MYNS || {};
>
> That will work as well.  I don't particularly care for it, but that's
> a matter of personal taste.

The one practical advantage to it I know of is that it's much easier
to introduce it in the sort of environment the OP describes, when
there is a team that needs to be convinced that namespaces are not
difficult. It's easy to point to a one-liner to demonstrate how easy
it is to start using namespaces.

--
Scott
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