• marcos@lemmy.world
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        8 months ago
        (+x) % 2 == 0
        

        If you forget for a second it’s Javascript, the language will turn back and bite you.

          • mindbleach@sh.itjust.works
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            8 months ago

            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.

          • marcos@lemmy.world
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            8 months ago

            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.

            • FiskFisk33@startrek.website
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              8 months ago

              Oh right that. I guess I was visualizing a scenario where you already checked for it being a number, such as a Number.isInteger(x)

              also, that suprises me a lot, you’d think this is one of the places where it treats stuff as numbers

    • Madlaine@feddit.de
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      8 months ago

      the is_even package does not provide much worth indeed because it simply negates is_odd and thereby all its benefit.

      It’s dependency is_odd on the other hand provides at least some additional checks (it also checks if the value is a valid integer below the max int value)

      And while I would indeed see uses for such methods (especially with the other checks, no simple oneliners) in some cases, especially in testing: This is stuff you write yourself, throw it in a e.g. NumberUtils class and everything is fine. You do never depend on an external library for that. The benefit (not spending a few seconds to write it) does not outweigh any of the drawbacks that come with external libraries.