A little "fun" fact about NaN: they are never equal to each other, even if it's the exact same value and variable. How can you check if a variable is NaN then?

A little "fun" fact about NaN: they are never equal to each other, even if it's the exact same value and variable. How can you check if a variable is NaN then? Well, if it's not equal to itself then it must be NaN!