nathan.wall at live.com
Fri Dec 14 09:12:53 PST 2012
> 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.
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