> But `myNaN === myNaN` is true if `myNaN = Object(NaN)`. That's my point. Normally testing for NaN can be done via `myNaN !== myNaN` but `Object(NaN)` throws a wrench in that. It would be great if there was 1 function that was able to detect NaN, instead of having libs step up and do it.
-JDD On Fri, Dec 14, 2012 at 9:12 AM, Nathan Wall <[email protected]> wrote: > > Wat? This seems to be a good reason to allow `Object(NaN)` and use the > > NumberWrapper brand as it cannot be tested via the normal way of > > `myNaN !== myNaN`. > > But `myNaN === myNaN` is true if `myNaN = Object(NaN)`. Testing against > the object is different. Nothing breaks. > > var myNaN = Object(NaN); > [ 1, 3, myNaN ].indexOf(myNaN); // => 2 > > Works as expected. The only problem which occurs is when you're working > with primitive NaN, in which case the only existing good ways to test for > it are `x !== x` and `typeof x == 'number' && isNaN(x)`. The purpose of > `Number.isNaN` is to provide a way to test this case which is easier to > read and understand. Note that if `x = Object(NaN)` both of these tests > fail. > > Nathan
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