> Le 27 oct. 2015 à 14:14, Boris Zbarsky <[email protected]> a écrit :
>
> On 10/27/15 4:35 AM, Claude Pache wrote:
>> it is that, for any callable object, it will return a string and not throw,
>> because it was so since the dawn of JS.
>
> It's totally false for random "host objects" with a [[Call]] in ES5, per spec
> and in at least some implementations. As you can tell in Firefox for example:
>
> Function.prototype.toString.call(document.createElement("object"))
>
> (though it does not throw for document.all in Firefox, for interesting
> implementation reasons).
>
>> That function will work (in the sense of: will return an answer; I'm not
>> judging the quality of that answer) with anything reasonable fed to it
>> (where "reasonable" excludes things like `(class { static toString() { throw
>> "pwnd!" }})`).
>
> Won't work with an HTMLObjectElement in at least some browsers. How
> "reasonable" that is, who knows.
>
> -Boris
You're right. But since `document.createElement("object")` does not inherit
from `Function.prototype`, the code (`f.toString()`) accidentally works after
all.
(I've tried not to be too smart in my example by writing `f.toString()` instead
of `Function.prototype.toString.call(f)`. Maybe I should have been even less
smart by defining an instance method on `Function.prototype` instead of a
static method on `Function`...)
—Claude
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