Le 20/01/2013 06:36, Kevin Smith a écrit :
It is not. At the exit of the get trap, the JS engine checks
whether invariants should be enforced for the given property on
the target. In your case, the runtime sees that the target has a
non-configurable non-writable property called 'foo' with 1 as
value. When you try to return 0, it will throw a TypeError because
of invariant violation. You can read about invariants at
http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxies#invariant_enforcement
Excellent - thanks for the link! One more: What is the reason for
not providing an API for unwrapping a proxy (e.g. your
proxyToFinalTarget)?
If anyone can unwrap proxies, then the security benefits they provide
are virtually non-existent akin to the Reflect API in Java.
It's possible to implement such a function yourself and expose it for
some of your proxies, but it should be an opt-in, not something
available by default to everyone in the language.
David
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