Object.isNumber returns true on NaN #336

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1. ta2edchimp commented on Oct 12, 2017

   

   ta2edchimp

   on Oct 12, 2017

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   Well, NaN is the value of a variable of type Number, that is "not a number".
   It's not that it hasn't been noticed until now (see StackOverflow) — it's according to the specs (JS type Number is an IEEE 754 float.

   Think, for example, of parseInt(input) as a function with a return value of type Number and with an input value that cannot be parsed as a numeric value.
   The return value must be of type Number, but does not need to be of a numeric value, thus NaN.