On Tue, Dec 8, 2009 at 1:29 PM, Breton Slivka <[email protected]> wrote: > The one that I use is > > function isArrayLike(i){ > return (typeof i !=="string") && i.length !== void (0); > } > > It might not be perfect, but it allows me to make certain assumptions > about the input that are useful enough. Keep in mind that an Array may > have a length of 5, and all those values are undefined, so {length:4} > could be used as a valid arrayLike, and that seems reasonable to me. >
On Tue, Dec 8, 2009 at 1:18 PM, Allen Wirfs-Brock <[email protected]> wrote: > Curiously, I don’t believe any of the “generic” functions for arrays and > array-like objects in section 15.4.4 actually depend upon such an > “array-like” test. They all simply use ToUint32 applied to the value of the > length property. If the length property doesn’t exist or its value isn’t > something that an a convertible representation of a number, the value 0 is > used as the length and not much happens. By this definition, all objects > are essentially array-like but many have no array-like elements. > > You've encapsulated here some of the reasoning behind my earlier test- Anything that passes my test is acceptable to any of the array prototype functions, but filters out two situations that I've found I didn't intend an object to be treated as an array. My usecase is overloaded functions that may also accept objects, and strings, and arraylikes, but I want a way to distinguish array-likes from objects and strings. _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
