It's worth pointing out that (3) sounds good, but it's an imperfect solution too. If Number.isNaN(num) is true, num === num will be false. Not just one, but several 64-bit patterns are considered NaN when represented as a floating-point number, so if all possible 64-bit values can be used, this could cause the opposite problem where inodes that are actually the same are considered not equal by JavaScript.