@Ryan, alias just creates an extra pointer to a method, so it doesn’t work with events.

@Ronny-Andre David is correct; the expense here is nil. It doesn’t invoke some methodology every time you call .each or anything. The alias function just applies it’s logic when it is parsed and after that you have two pointers to the same method.

As for using this to create your own fun names for things, you certainly could. I think that a far more powerful method for creating your own functionality for native elements is the custom methods that MooTools allows you to define. For instance, look at the element shortcuts in Fx.Tween:

Element.implement({
//there are other shortcuts, but let’s just look at highlight…
highlight: function(start, end){
if (!end){
end = this.retrieve(‘highlight:original’, this.getStyle(‘background-color’));
end = (end == ‘transparent’) ? ‘#fff’ : end;
}
var tween = this.get(‘tween’);
tween.start(‘background-color’, start || ‘#ffff88′, end).chain(function(){
this.setStyle(‘background-color’, this.retrieve(‘highlight:original’));
tween.callChain();
}.bind(this));
return this;
}
});

Using implement (combine with element storage) you can create a lot of customized behavior. For instance, let’s say you liked jQuery’s method for adding click events.

@Ryan: I don’t believe that alias would be applicable to your example.