Le 12/01/2013 21:58, Andrea Giammarchi a écrit :
that is a (quick/imperfect/asexample) way to detect a proxy while I
understand these should not be detectable.
{} and [] also return true to your test, but they're not proxies. You
cannot use an imperfect test to prove a point.
As I (and others now) said, the DOM, in order to be self-consistent (and
have performance in operations like selector matching) can only use
objects it created through HTML parsing or methods like
document.createElement. It will refuse any other object, proxy or not.
With tree manipulation methods (like appendChild), the only relevant
test you can be making is "is this object a DOM created genuine node?".
This rules out *any* object. This includes proxies to node
Consider that as conditional check after node instanceof Element in
order to know if that node is usable or not as DOM element.
Object.create(Element.prototype)?
There, a way to simulate an isProxy method and it does not matter if
that's silly ... is possible
The possibility to use proxies in the DOM tree was ruled out because of
the selector matching use case. If you have a solution to put proxies in
the DOM tree without ruining selector matching perf, you will be listened.
David
On Sat, Jan 12, 2013 at 11:24 AM, Brendan Eich <[email protected]
<mailto:[email protected]>> wrote:
This is silly.
I can use the closure pattern to vend objects that do not satisfy
the internal constraints the DOM imposes on some of its objects.
No proxies in sight.
So why is the method you wrote named "isDOMProxy" and whatever in
the world does it have to do with Proxy?
/be
Andrea Giammarchi wrote:
and in both cases you would have ...
Proxy.isDOMProxy = function (node) {
try {
document.documentElement.appendChild(node);
document.documentElement.removeChild(node);
return false;
} catch(gotcha) {
return true;
}
};
that's why I have talked about inconsistencies all over at the
very beginning of this thread :)
br
On Sat, Jan 12, 2013 at 10:26 AM, Nathan Wall
<[email protected] <mailto:[email protected]>
<mailto:[email protected] <mailto:[email protected]>>>
wrote:
Nathan wrote:
>
> Hey Tom, I think you missed my point. The point was that in
David and Boris' discussion they agreed that the DOM
should throw
if it is given a Proxy in `appendChild`. That sounded to
me like
it presumed that the DOM had a magical ability to distinguish
between DOM objects and their proxies. That seemed to
contradict
the point David made that Proxies should not be
distinguishable
from their targets (e.g. the no `Proxy.isProxy` decision).
If real
DOM had a way to determine if something was a proxy (with
a target
of a *real* DOM node) and throw but there was no way for an
emulated DOM (in a non-DOM environment) to determine if an
object
was a proxy with a target to an emulated DOM node or just
a plain
emulated DOM node, then the DOM has magical abilities that the
emulated DOM can't have. That was my concern.
>
> David's reply works, though, I think. He stated that
since you
have to create DOM nodes using a method of the DOM itself
(`document.createElement`, `document.createTextNode`), then
emulated DOM could track all objects created and compare them
against objects passed into `appendChild`, and since a
proxy would
have a different object identity from its target, the
emulated DOM
would have a way to distinguish proxies from their targets.
>
> Nathan
In short, if real DOM can throw when given a proxy of a
real DOM
node, fake DOM should also be able to throw when given a
proxy of
a fake DOM node.
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