Of all the things to complain about, he chose one that is not JavaScript's fault: the fact that NaN is a number and equality on NaN is not reflexive is a proper

Of all the things to complain about, he chose one that is not JavaScript's fault: the fact that NaN is a number and equality on NaN is not reflexive is a property of the floating point number standard. Try it in some other language you have lying around, like Python: >>> type(float('nan')) <type 'float'> >>> float('nan') == float('nan') False Also Haskell: Prelude> 0/0 NaN Prelude> 0/0 == 0/0 False If anything, it's refreshing that JavaScript does behave like other languages in this case!