Rails spinoffs - Jun 2008 - Determining the class of an Object

I have in my code several classes defined using prototype.

var Conversation = Class.create({ (methods) });
var Friend = Class.create({ (methods) });

And I have a variable that can hold an instance of either of both
classes.

var A = new Friend();

Is there a way of checking which type it is?

I''m looking for something equivalent to:

If (A Is Friend) { }
elseif (A Is Conversation) { }

or...
If (typeof A Is Friend) { }

Is there something like that?
I can check for the existence of a member. For example, I know
Conversations have a method called "xxx", and Friends do not, so I can
do:

If (typeof A.xxx != ''undefined'') { }

But that''s bound to be broken when I add an "xxx" method to
Friend.
Plus, I have many different classes a variable can hold, so these
tests can get quite long-winded at times.

Any ideas?
Sorry if this has an obvious answer, I haven''t been able to find it.

Thanks in advance!
Daniel Magliola
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if (A instanceof Friend) { ... }

-Fred

On Thu, Jun 5, 2008 at 1:24 PM, Daniel Magliola
<dmagliola-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> I have in my code several classes defined using prototype.
>
> var Conversation = Class.create({ (methods) });
> var Friend = Class.create({ (methods) });
>
> And I have a variable that can hold an instance of either of both
> classes.
>
> var A = new Friend();
>
> Is there a way of checking which type it is?

-- 
Science answers questions; philosophy questions answers.

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