Just a bump here since I'm curious too! :)
I just kind if take things like jQuery for granted and use and abuse
them without really knowing or caring how it does what it does, so
long as it works :)
(I guess that's a textbook OOP abstraction definition lol)
Anyway, wanna know the answer too if anyone has it...
-Alex
On Sep 16, 9:56 pm, Andrei Maxim <[EMAIL PROTECTED]> wrote:
> Hi all,
>
> I've recently grabbed the latest edition of the Rhino book and I'm
> trying to build some small JavaScript libraries in order to get the
> hang of coding in JS. I've been also reading lots of blog posts and
> I've been looking at the code of several major JS frameworks and
> libraries, like jQuery, Prototype and script.aculo.us and I'm trying
> to understand why the author wrote that code.
>
> For some reason, I've been growing very fond of the pattern used in
> jQuery to create the jQuery object. Here's the code I'm talking about,
> taken from v1.2.6:
>
> var jQuery = window.jQuery = window.$ = function( selector, context )
> {
> // The jQuery object is actually just the init constructor 'enhanced'
> return new jQuery.fn.init( selector, context );
>
> };
>
> [...]
>
> jQuery.fn = jQuery.prototype = {
> init: function( selector, context ) {
> // Make sure that a selection was provided
> selector = selector || document;
>
> // Handle $(DOMElement)
> if ( selector.nodeType ) {
> this[0] = selector;
> this.length = 1;
> return this;
> }
> [...]
>
> };
>
> // Give the init function the jQuery prototype for later instantiation
> jQuery.fn.init.prototype = jQuery.fn;
>
> When I tried to add my custom object, I had some problems with
> accessing the functions I defined inside jQuery.prototype. Only after
> a couple of hours I added a line similar to jQuery.fn.init.prototype =
> jQuery.fn and then it magically worked.
>
> However, I don't get what's going on.
>
> From what I understood reading JavaScript docs, "jQuery.fn =
> jQuery.prototype" means that we "reference" jQuery object's prototype
> and I'm guessing this is used just to simplify the code (I might be
> extremely wrong on this). Also, the defined functions are shared by
> each jQuery object.
>
> But why do we need to add "jQuery.fn.init.prototype = jQuery.fn" for
> things to work?
>
> Thanks a lot,
> Andrei
