(+x) % 2 == 0
If you forget for a second it’s Javascript, the language will turn back and bite you.
This evaluates to NaN for some reason:
'10' % 0
Since JS doesn’t really differentiate strings from numbers, except on the places it does, it makes sense to make sure you are working with numbers.
the remainder operator should return a number or a NaN right? do we actually need the triple here?
JS is a language where [1,2,11].sort() returns [1,11,2].
And if you use a variable instead of a bare array, half the functions are side-effectful, as determined by coin toss.
And if you try declaring that variable with new Array(3).map() then it will ignore all 3 indices, because undefined is real enough to be enumerated, but not real enough to be iterated, because, and I cannot overstress the importance of this principle in Javascript, go fuck yourself. Go fuck yourself is why.
Array(3) doesn’t create [undefined, undefined, undefined, ]; it creates [/* hole */, /* hole */, /* hole */, ]. The holes don’t set any property on the array whatsoever, so they are skipped when iterating. How this makes sense, I can’t tell you.
