Could you post a use example?
In this case, I usualy create a simple class not derived from Element
and a "maker function" to extend DOM elements with this class
prototype.
I am not sure at all it is the best approach but it works and is
relatively easy to maintain.
It looks like this (untested) for exemple if you want to cast a LI tag
into a kind of tree:
function mkTree(domElement) {
domElement = $(domElement) || new Element('li');
Object.extend(domElement,Tree.prototype);
domElement.initialize();
return domElement;
}
var Tree = Class.create({
initialize: function() {this.addClassName('tree'); },
createNode: function(...) {.../... }
});
You may have to play with Array.shift and Function.call if you want to
have extra parameters to your "constructor" (I've never needed it yet
but it should be possible).
Eric
Note: I've never tried to override a native method and I am kind of
certain it would not work :o)
On Apr 7, 9:11 pm, Guss <[email protected]> wrote:
> On Mar 25, 12:02 am, Glen <[email protected]> wrote:
>
> > I would like to use Prototype's class inheritance to derive a class
> > from Element as below:
> > The current structure of Element and Class does not support such.
> > I was wondering if anyone had anything more elegant.
>
> I have the same issue - I want to create my own classes that "inherit"
> from standard DOM elements, so I can do something like:
> var Button = Class.create(Element, {
> initialize: function($super, content) {
> $super('button');
> this.update(content);
> }});
>
> document.body.appendChild(new Button("submit"));
>
> But as you noted, Element in prototype is not a prototype Class that
> can be extended using Class.create. I decided not to muck about with
> that and instead write something else. So I create
> Class.createElement() that works like as you would expect, with the
> very serious caveat that you can't override most native methods (not
> sure why - I can override some, but not others).
>
> The implementation looks like this (and is mostly copied from
> Class.create):
>
> Class.createElement = function(tagname, impl) {
> var IS_DONTENUM_BUGGY = (function() {
> for ( var p in { toString : 1 }) {
> // check actual property name, so that it works with
> augmented
> // Object.prototype
> if (p === 'toString')
> return false;
> }
> return true;
> })();
>
> return function() {
> var elm = new Element(tagname);
> properties = Object.keys(impl);
>
> // IE6 doesn't enumerate `toString` and `valueOf` (among
> other built-
> in
> // `Object.prototype`) properties,
> // Force copy if they're not Object.prototype ones.
> // Do not copy other Object.prototype.* for performance
> reasons
> if (IS_DONTENUM_BUGGY) {
> if (impl.toString != Object.prototype.toString)
> properties.push("toString");
> if (impl.valueOf != Object.prototype.valueOf)
> properties.push("valueOf");
> }
>
> for ( var i = 0, length = properties.length; i < length; i++)
> {
> var property = properties[i], value = impl[property];
> if (Object.isFunction(value) &&
> value.argumentNames()[0] ==
> "$super") {
> var method = value;
> value = (function(m) {
> return function() {
> return elm[m].apply(this,
> arguments);
> };
> })(property).wrap(method);
>
> value.valueOf = method.valueOf.bind(method);
> value.toString = method.toString.bind(method);
> }
> impl[property] = value;
> }
> Object.extend(elm,impl);
> elm.initialize.apply(elm,arguments);
> return elm;
> };
>
> };
>
>
--
You received this message because you are subscribed to the Google Groups
"Prototype & script.aculo.us" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/prototype-scriptaculous?hl=en.
