Hi Sebastian, Could you clarify why trapping instanceof is required for promises? It seems your use case can be addressed already using the current Proxy API: if `FP` is a function proxy, then `obj instanceof FP` will query `FP` for its `prototype` property (as per the default algorithm) by calling the function proxy's `get` trap. Inside that `get` trap, you could check whether the prototype is unresolved or "far" and if so, throw an exception.
Cheers, Tom 2010/11/18 Sebastian Markbåge <[email protected]> > I thought I'd make the case for the "instanceof trap" > in strawman:proxy_extensions - beyond multiple inheritance. I'm sure this > point has been made before at some point. > > This is useful to implement various forms of promises using proxies. The > prototype can be resolved at a later time perhaps after some IO or lazy > operation. This should be able to fail if the promise is currently > unresolved or "far". > > It's the final piece missing to preserve "the invariants that keep the JS > lucid dream". > > I'm also curious to hear any objections to this proposal. I don't see the > same issues as with mutable prototypes being applicable to proxies. > > Sebastian Markbåge > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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