Yeah it sounds complicated... I'm kinda newbe to this, I hope you
don't mind if I ask these silly questions
I thought the anonymous function got executed on this line
for ( var i in properties ) {
(function(){
this[ "get" + i ] = function() {
return properties[i];
};
this[ "set" + i ] = function(val) {
properties[i] = val;
};
}).call(this)--> EXECUTE! (and use actual value of i)
// now go on with the next i
; }
Isn't this the "logical" way of seeing it? what am I missing?
On Thu, Dec 18, 2008 at 3:38 PM, Balazs Endresz
<balazs.endr...@gmail.com> wrote:
>
> this[ "set" + i ] = function(val) {
> properties[i] = val;
> };
>
> This code only defines a function but doesn't execute its contents
> right now, and as functions "capture" the variables defined outside of
> them if you change the value of i then it will "change" in properties
> [i] too. In other words the `i` in properties[i] is the same that you
> use for the loop.
>
> If you use a closure you can define a local variable that gets the
> value (not the reference!) of the current index so that won't change
> afterwards.
>
> Sounds complicated but it really isn't - once you get it :)
>
> On Dec 18, 5:52 pm, "pablo fernandez" <fernandezpabl...@gmail.com>
> wrote:
>> That Does it too!!
>>
>> I still don't get why 'i' keeps always the last value if you don't do
>> var i = j; :S
>>
>> On Thu, Dec 18, 2008 at 1:11 PM, Balazs Endresz
>>
>>
>>
>> <balazs.endr...@gmail.com> wrote:
>>
>> > I've just had a look at it and where this issue comes up in the book
>> > there's a new variable declared (like on page 153). No need to pass
>> > the argument this way, moreover not that easy to mistype:
>>
>> > for ( var j in properties ) { (function(){
>> > var i=j;
>> > ...
>>
>> > I can't believe no one has spotted
>> > this:http://www.apress.com/book/errata/275
>>
>> > On Dec 18, 4:53 pm, Pablo Fernandez <fernandezpabl...@gmail.com>
>> > wrote:
>> >> That did it, although I had to add this too
>>
>> >> -- }).call(this,i);
>>
>> >> in order to pass the parameter
>>
>> >> Thanks Balazs!!!
>>
>> >> On 18 dic, 12:29, Balazs Endresz <balazs.endr...@gmail.com> wrote:
>>
>> >> > Oops, I didn't notice it: you have to pass the `i` variable too:
>> >> > for ( var i in properties ) { (function(i){
>>
>> >> > That's why you need the closure at all. Without that you will get the
>> >> > last property from all getters.
>>
>> >> > The reference of `this` will always change if you put it in an
>> >> > additional function, doesn't matter if it's inside an instantiated
>> >> > object. Well, you can call that either design error or feature too :)
>>
>> >> > On Dec 18, 4:18 pm, Pablo Fernandez <fernandezpabl...@gmail.com>
>> >> > wrote:
>>
>> >> > > another thing... why inside the anonymous function 'this' refers to
>> >> > > 'window' ?? it's totally misleading...
>>
>> --
>> Fernandez, Pablo.
> >
>
--
Fernandez, Pablo.
