Just a quick one...
what's the correct way to format a javascript function?
I see it like this:
function doThis(){
}
and like this:
doThis = function(){
}
Or maybe it make no difference. Please let me know whats best or if they both have different rasons or purposes.
Cheers
C
They are two different things, although they both create a function (and assign it to a variable).
function name () {
}
Is a function-statement (or "function declaration"). It is only legal to appear as a top-level script element or directly as an element of a function: that is, it is not legal for a function-statement to appear inside an if, or while, etc. All function statements are "lifted" to the top of the function (or script), thus the following is valid:
a()
function a () { alert("a") }
In the form:
variable = function name () {} // or variable = function () {}
The function keyword is in a function-expression context: it creates a new function-object and the resulting function-object (just a "normal value") is assigned to variable. The following is not valid because function-expressions are not lifted.
var b
b() // oops, does not evaluate to a function-object yet!
b = function b () { alert("b") }
All that being said, the "correct way" is to use the function-statement ("function declaration") form unless there is reason to do otherwise.
Happy coding.
See also:
There is an important and also useful difference between those syntaxes.
In OOP it is very useful to use encapsulation, which is a mechanism for restricting access to other objects. The difference between public and private vars/functions in javascript could stated like this:
function Color(value)
{
// public variable
this.value = value; // get from arguments
// private variable
var _name = "test";
// public function
this.getRandomColor = function( )
{
return Math.random() * 0xFFFFFF;
}
// private function
function getNiceColor()
{
return 0xffcc00;
}
}
The public variables and functions inside the a color-instance are accessible:
// create instance of Color
var color = new Color(0xFF0000);
alert( color.value ); // returns red color
alert( color.getRandomColor() ); // returns random color
Private variables and functions cannot be accessed from the color-instance:
var color = new Color(0x0000FF);
alert( color.getNiceColor() ); // error in console; property does not exist, because function is private.
alert( color._name ); // error in console; property does not exist, because variable is private.
NOTE
It could be better to use good-old prototypes when using public functions, because this method of coding could cause problems with inheritence.
