The type of the target is what affects typeof, indirectly by setting the [[Call]] value. If an `apply` or `construct` trap handler is given and the target isn't a function, they are ignored. See step 7 in https://www.ecma-international.org/ecma-262/9.0/index.html#sec-proxycreate
On Tue, Dec 4, 2018 at 2:08 PM Isiah Meadows <[email protected]> wrote: > BTW, `typeof new Proxy({}, {apply() { return 1 }})` returns > `"object"`, not `"function"`. Not sure this is any different. > > ----- > > Isiah Meadows > [email protected] > www.isiahmeadows.com > On Tue, Dec 4, 2018 at 2:02 PM Jordan Harband <[email protected]> wrote: > > > > What would `typeof` return on a callable object? There's a lot of code > on the web that uses a typeof of "function" to determine if something is > safe to call. There's also a lot of code on the web that uses a typeof of > "function" to do type detection. How would you suggest a callable object > navigate these potentially conflicting constraints? > > > > On Tue, Dec 4, 2018 at 10:07 AM T.J. Crowder < > [email protected]> wrote: > >> > >> On Tue, Dec 4, 2018 at 5:02 PM Sultan > >> <[email protected]> wrote: > >> > > >> > Something along the lines of Symbol.iterator protocol for defining > >> > callback objects i.e: Symbol.callable: > >> > >> That's interesting. What's the primary motivation? Binding the data? > That's easily done with a closure ([fiddle[1]): > >> > >> ```js > >> const obj = (() => { > >> let value = 'value'; > >> return () => value; > >> })(); > >> > >> console.log(obj() === 'value'); // true > >> ``` > >> > >> It's a bit more verbose than one would like, but usually that's washed > out by the implementation (which is really trivial above). > >> > >> You can also do it with a Proxy on a function, but it doesn't really > buy you anything. > >> > >> Be interested to know more about why you want non-function callable > objects. > >> > >> -- T.J. Crowder > >> > >> [1]: http://jsfiddle.net/8qvpc7Lh/ > >> _______________________________________________ > >> es-discuss mailing list > >> [email protected] > >> https://mail.mozilla.org/listinfo/es-discuss > > > > _______________________________________________ > > es-discuss mailing list > > [email protected] > > https://mail.mozilla.org/listinfo/es-discuss > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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