Javascript Code Styling

[Tom Cole]

I'm starting to do more quantity of javascript coding and thought this
might be a good time to investigate code styling. I primarily develop
in Java and currently use the code styling techniques spelled out for
Java.

For example, in my code blocks ( {} ) I always place the starting brace
on the same line as the first line of code. For example:

function myFunction {

But I've also noticed a lot of developers move it to the next line:

function myFunction
{

I also place a semicolon at the end of each line, although I see it's
also not mandatory.

Third (and lastly) I also declare all Objects in first letter uppercase
and all member variables/functions in lowercase. For example:

function MyObject() {

var myFirstMemberVa r;

function doSomething() {
....
}
}

Is there a coding standard for Javascript? Do my current practices seem
feasible?

Thanks in advance.

[Laurent Bugnion]

Hi,

Tom Cole wrote:

I'm starting to do more quantity of javascript coding and thought this
might be a good time to investigate code styling. I primarily develop
in Java and currently use the code styling techniques spelled out for
Java.

A few years ago, when we (I work at Siemens) started working on our
current wep application, we decided to write our own JavaScript coding
guidelines. Mostly, they are inspired of our C/C++ coding guidelines and
also of Java guidelines (because code found online mostly follows the
Java guidelines for capitalization for example).

For example, in my code blocks ( {} ) I always place the starting brace
on the same line as the first line of code. For example:

function myFunction {

But I've also noticed a lot of developers move it to the next line:

function myFunction
{

This is mostly a matter of taste. Our guidelines allow both but
recommend the second one, which we find is more readable. If you work
with Visual Studio 2003/2005, it's easy to configure

I also place a semicolon at the end of each line, although I see it's
also not mandatory.

Not mandatory in JavaScript, but it's very recommended. We made it
mandatory in our guidelines. If you use a code minimizer like JsMin,
placing more than one statement on one single line, then the ';' is
mandatory anyway.

Third (and lastly) I also declare all Objects in first letter uppercase
and all member variables/functions in lowercase. For example:

function MyObject() {

var myFirstMemberVa r;

function doSomething() {
....
}
}

This is also what we recommend. However, we also recommend hungarian
notation for variables. This goes against our C# guidelines, but has a
reason: In JavaScript, objects are not strongly typed. Thus they may
contain a type first, and then another type. However, to avoid
confusion, our guidelines specify that this must be avoided, and a
variable must carry a single type all along its life. To facilitate
this, hungarian notation is used, for example strMessage (string),
iValue (integer numbers), fValue (float numbers), etc... Note that
JavaScript doesn't differentiate integer and float, so it's really just
to help the developer.

Generally, JavaScript coders follow the Java naming guidelines, like you.

Is there a coding standard for Javascript? Do my current practices seem
feasible?

Thanks in advance.

Yes, they seem very reasonable.

HTH,
Laurent
--
Laurent Bugnion, GalaSoft
Software engineering: http://www.galasoft-LB.ch
PhotoAlbum: http://www.galasoft-LB.ch/pictures
Support children in Calcutta: http://www.calcutta-espoir.ch

[Richard Cornford]

Laurent Bugnion wrote:
<snip>

>For example, in my code blocks ( {} ) I always place the
starting brace on the same line as the first line of code.
For example:

function myFunction {

But I've also noticed a lot of developers move it to the
next line:

function myFunction
{

This is mostly a matter of taste. Our guidelines allow both
but recommend the second one, which we find is more readable.

<snip>

I have a feeling that the one of the two that is found more readable by
individuals is the one with which they are more familiar. I find the
former more readable. But I suspect that the most important thing is to
be consistent and use only one or the other (certainly within any single
project, and probably within any single company).

Generally, JavaScript coders follow the Java naming
guidelines, like you.

I certainly do.

>Is there a coding standard for Javascript? Do my current
practices seem feasible?

Thanks in advance.

Yes, they seem very reasonable.

Absolutely.

Richard.

[Kevin Darling]

Laurent Bugnion wrote:

Hi,

Tom Cole wrote:

But I've also noticed a lot of developers move it to the next line:
function myFunction
{

This is mostly a matter of taste. Our guidelines allow both but
recommend the second one, which we find is more readable.

We do a lot of JS, and we prefer using the next line also. The old way
of using the same line is no doubt related to early terminal / memory
problems.

[...] hungarian notation is used, for example strMessage (string),
iValue (integer numbers), fValue (float numbers), etc... Note that
JavaScript doesn't differentiate integer and float, so it's really just
to help the developer.

We use these, plus oReference for objects.

Cheers , Kev

[Laurent Bugnion]

Hi Richard,

Richard Cornford wrote:

>>This is mostly a matter of taste. Our guidelines allow both
but recommend the second one, which we find is more readable.

<snip>

I have a feeling that the one of the two that is found more readable by
individuals is the one with which they are more familiar. I find the
former more readable. But I suspect that the most important thing is to
be consistent and use only one or the other (certainly within any single
project, and probably within any single company).

Yes. We talked for a while about it, and decided to let the programmers
decide (for the record, the development lasted 2.5 years, involved about
30000 lines of JavaScript code, and we had 6 developers writing
JavaScript. Most of them had zero experience with the language, but are
very good C/C++/C# programmers. After a few internal courses, they were
totally up to the task). Mostly in my firm, the second form (bracket on
a different line) is used. This is probably why we found it more
readable. But as I said, it's very much personal.

Greetings,
Laurent
--
Laurent Bugnion, GalaSoft
Software engineering: http://www.galasoft-LB.ch
PhotoAlbum: http://www.galasoft-LB.ch/pictures
Support children in Calcutta: http://www.calcutta-espoir.ch

[Laurent Bugnion]

Hi,

Kevin Darling wrote:

Laurent Bugnion wrote:

>>[...] hungarian notation is used, for example strMessage (string),
iValue (integer numbers), fValue (float numbers), etc... Note that
JavaScript doesn't differentiate integer and float, so it's really just
to help the developer.

We use these, plus oReference for objects.

Cheers , Kev

Yes. We actually have more than these. For example, we also use "n" for
nodes (objects returned by document.getEle mentById). We made a list of
prefixes and strongly encourage the developers to use it. It's no
problem for them, as they were using hungarian notation in C++. It's
rather a problem that they have to abandon it in C# (we follow
Microsoft's recommendation for C#, for many reasons, including sharing
code with other Siemens divisions).

Greetings,
Laurent
--
Laurent Bugnion, GalaSoft
Software engineering: http://www.galasoft-LB.ch
PhotoAlbum: http://www.galasoft-LB.ch/pictures
Support children in Calcutta: http://www.calcutta-espoir.ch

[scriptguru]

Tom Cole напи�ав:

For example, in my code blocks ( {} ) I always place the starting brace
on the same line as the first line of code. For example:

function myFunction {

But I've also noticed a lot of developers move it to the next line:

function myFunction
{

Few days ago I found JS Editor and Code Chameleon developed by C-Point.
That tools can reformat any source and may be very useful sometimes. It
can be used as a reformatter ot beautifier.

I also place a semicolon at the end of each line, although I see it's
also not mandatory.

The semicolons may became a subject of one more Holy War :)
All programmers who used C/C++ before JS always use semicolons. I never
used C/C++ (we learned Pascal in school and college) and use semicolons
rarely. I think it is a benefit of language - free usage of semicolons.
And if some code minifier kills your code because of missing semicolons
then it is bad code minifier. Good code minifier never acts like this.

[Richard Cornford]

sc********@gmai l.com wrote:

Tom Cole напи�ав:

<snip>

>I also place a semicolon at the end of each line, although I
see it's also not mandatory.

The semicolons may became a subject of one more Holy War :)
All programmers who used C/C++ before JS always use semicolons.

This would probably be true of anyone coming form any language that
required semicolons to terminate lines. Overall Java probably has the
biggest influence on code styling in javascript (though maybe that is
not such a good idea).

I never used C/C++ (we learned Pascal in school and college) and use
semicolons rarely. I think it is a benefit of language - free usage of
semicolons.

Javascript doesn't really have free use of semicolons. Intact they are
not even optional, they just may be inserted automatically so do not
need to be in the source code. the problem with that is that you need
to appreciate when they will be inserted when writing anything but the
most 'normal' code. For example, two consecutive instances of the
inline execution of a function expression:-

(function(){
...
})();
(function(){
...
})();

- Omit the semicolons to give:-

(function(){
...
})()
(function(){
...
})()

- and the second parenthesised function expression becomes an argument
to a call to the return value from the call to the first function
expression, and the final set of parenthesise then become a call the
return value from that call. That is, something along the lines of:-

(((function(){; })())(function( ){;}))();

- (which is completely legal and valid javascript)

The error is likely to be along the lines of "function expected" on the
line at the start of the second function expression, not easy to work
out what happened.

And if some code minifier kills your code because of missing
semicolons then it is bad code minifier. Good code minifier
never acts like this.

Which is not a reasonable comment on JsMin as JsMin requires that its
input first passes JsLint, and JsLint insists upon
statement-terminating semicolons as one of its 'best practice' criteria
for source code.

Richard.

[Douglas Crockford]

Tom Cole wrote:

For example, in my code blocks ( {} ) I always place the starting brace
on the same line as the first line of code. For example:

function myFunction {

But I've also noticed a lot of developers move it to the next line:

function myFunction
{

I prefer the first form because it works better when a function literal is used
inline as an expression, particularly when passing a function as a parameter. In
that circumstance (which I use a lot), the second form reads badly.

I also place a semicolon at the end of each line, although I see it's
also not mandatory.

It is wise to include the semicolons. Semicolon insertion was intended to make
JavaScript more reliable, but dependence on it makes programs less reliable.

Third (and lastly) I also declare all Objects in first letter uppercase
and all member variables/functions in lowercase. For example:

function MyObject() {

var myFirstMemberVa r;

function doSomething() {
....
}
}

What you are calling an Object there is usually called a Constructor. It is very
good practice to capitalize the names of constructors. The reason is that
calling a constructor without the new prefix can cause clobbering of the global
object, which is very bad. There is no compile-time or run-time notification of
this error. The only defense we have is a coding convention that we should use a
new prefix when invoking a capitalized function. (The exceptions are when
invoking String, Number, and Boolean which should never be called with the new
prefix.)

Is there a coding standard for Javascript? Do my current practices seem
feasible?

This is what I use: http://javascript.crockford.com/code.html

[scriptguru]

Richard Cornford напи�ав:

Javascript doesn't really have free use of semicolons. Intact they are
not even optional, they just may be inserted automatically so do not
need to be in the source code. the problem with that is that you need
to appreciate when they will be inserted when writing anything but the
most 'normal' code.

Yes, I know that JS parser/interpreter automaticaly inserts semicolons.
Thats why I love it :)
I am javascript/actionscript developer with ~6 years of experience. My
applications sometimes became really complicated (and I trying to use
full potential of JS). But no even one "Missing semicolon" errors or
any other problem with semicolons for last years.

And if some code minifier kills your code because of missing
semicolons then it is bad code minifier. Good code minifier
never acts like this.

Which is not a reasonable comment on JsMin as JsMin requires that its
input first passes JsLint, and JsLint insists upon
statement-terminating semicolons as one of its 'best practice' criteria
for source code.

I never said that JsMin or JsLint are bad or even not good enough. But
I saw many code minifiers that will destroy code if semicolons are not
used.

Val Polyakh
trickyscripter. com