We maintain the invariant that the typeof of an object is stable -- it never varies over time. An object is callable iff its typeof is 'function'. By making the callability *and* the typeof of the proxy dependent on its target, the two stay consistent.
On Wed, Mar 2, 2016 at 6:51 AM, Олег Галабурда <[email protected]> wrote: > Yes, correct. I want to be able to make a callable Proxy for non-callable > objects and don't understand why Proxies are having these restrictions. > As you can see I, and any other developer, can easily bypass this > restriction and make a wrapper function that actually will be never called > and just redirect calls made on Proxy to a method of an object. > Exactly. You are doing the right thing. This demonstrates that there is no loss of intended generality from imposing this restriction. It imposes a minor inconvenience for an uncommon case, as the price of being more straightforward for common cases. > If "apply" trap will be allowed for any type of targets this will make > life easier :) > > 2016-03-02 16:19 GMT+02:00 Claude Pache <[email protected]>: > >> >> Le 2 mars 2016 à 13:21, Олег Галабурда <[email protected]> a écrit : >> >> Hi! >> >> I'm currently working on project that allows to manipulate objects passed >> from Worker. >> https://github.com/burdiuz/js-worker-interface >> >> It creates wrapper objects that record actions applied to this object and >> send commands to Worker. The problem is, when request is made I cannot know >> what kind of object is this, so in case of function I should give ability >> to make calls on the wrapper object. >> As example, this code: >> >> var api = new WorkerInterface('../webworker.js'); >> api.requestTime(); >> >> When "requestTime" was requested, it calls "get" and immediately returns >> new Proxy to serve function call. But at time when Proxy is created I do >> not know if that is function or not. Now I passed "apply" limitation by >> adding wrapper function and make Proxy think it works with function. >> >> https://github.com/burdiuz/js-worker-interface/blob/master/source/interface/proxy.js >> >> >> If I guess correctly your issue, you would like to have something similar >> to: >> >> foo.bar // not-a-function >> >> and: >> >> foo.bar() // a method call >> >> ? Indeed, that is not possible in JavaScript (and that limitation is not >> restricted to proxies). >> >> >> I found in discussions why "call" trap was rejected, but didn't find >> anything about restricting "apply" trap to functions only. >> >> >> Probably because "X is a function" is, by design, strictly equivalent to >> "X is callable"? >> >> —Claude >> >> > > > -- > Oleg Galaburda > http://blog.actualwave.com/ > http://jsinterface.googlecode.com/ > http://guibuilder.org/ > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > -- Cheers, --MarkM
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