0.2 + 0.1 === 0.3 That's not really a JS problem, that's a floating point problem. Plenty of languages will have the same issue. +!![] "" - - "" (null - 0) + "0" Calling these things weird is fair enough but I can't help thinking this is code you'd never actually write outside of the context of a "Look how weird JS is!" post. It's like picking examples from the Annual Obfuscated C Contest to show how hard it is to un…
More accurately it's a binary problem. 0.1 and 0.3 have non-terminating representations in binary, so it's completely irrelevant whether you're using fixed or floating point.
Any number that can be represented as the sum of powers of 2 and 5 have a terminating decimal representation, whereas only numbers that can be represented as the sum of powers of 2 have a terminating representation in binary. The latter is clearly a subset of the former, so it seems obvious that we should be using decimal types by default in our programming languages.
Oh well.