Prototype bug or feature?

[a.riser@web.de]

Hello

When using *this* in an Array#each or Hash#each-loop this references
*window*. Is this intentional (I can't believe it)? An example here:
http://www.banza.net/jstest/this.html .

The code there is:

var Test = Class.create({
initialize: function(){
this.location = '----------- eeehhhh ---------------';
this.array = $A([1])
this.hasch = $H({key_one:'va l_one'});
},
procede: function(){
document.writel n(' this.location: "'+this.locatio n+'"<br />');
this.array.each ( function( item ){
document.writel n(' this.location: "'+this.locatio n+'"<br />');
});
document.writel n(' this.location: "'+this.locatio n+'"<br />');
this.hasch.each ( function( item ){
document.writel n(' this.location: "'+this.locatio n+'"<br />');
});
}
});
x = new Test();
x.procede();

I'm using of course Prototype 1.6.0.2.

Greets, a.

[Joost Diepenmaat]

Re: Prototype bug or feature?

a.riser@web.de writes:

Hello
>
When using *this* in an Array#each or Hash#each-loop this references
*window*. Is this intentional (I can't believe it)? An example here:
http://www.banza.net/jstest/this.html .

Dunno if it's intentional; I don't use Prototype, but it matches the
behaviour of Array.prototype .forEach in JavaScript 1.6:

<http://developer.mozilla.org/en/docs...avaScript_1.5_
Reference:Objec ts:Array:forEac h>

array.forEach(c allback[, thisObject]);

IOW, in JS 1.5 you must pass a second argument specifying the <<this>>
object, otherwise it'll be the global object (window).


--
Joost Diepenmaat | blog: http://joost.zeekat.nl/ | work: http://zeekat.nl/

[a.riser@web.de]

Re: Prototype bug or feature?

On 3 Mai, 19:13, Joost Diepenmaat <jo...@zeekat.n lwrote:

<http://developer.mozilla.org/en/docs...avaScript_1.5_
Reference:Objec ts:Array:forEac h>
>
  array.forEach(c allback[, thisObject]);

Thank you, it's indeed the same in Prototype (now I found it in the
docs - shame on me):

...
this.hasch.each ( function( item ){
document.writel n(' this.location: "'+this.locatio n+'"<br />');
}, this);
...

works as I would have expected without the second parameter.

[jdalton]

Re: Prototype bug or feature?

In fact Prototype uses the Native Array#forEach when available:
if (Object.isFunct ion(Array.proto type.forEach))
Array.prototype ._each = Array.prototype .forEach;

Also for future reference the Prototype user mailing list is here:

http://groups.google.com/group/rubyonrails-spinoffs

- JDD