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[-] FiskFisk33@startrek.website 32 points 9 months ago* (last edited 9 months ago)

is this really a feature not built into Java Script?

x % 2 == 0

[-] marcos@lemmy.world 28 points 9 months ago
(+x) % 2 == 0

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

[-] Kindness@lemmy.ml 8 points 9 months ago

(+x) % 2 === 0

[-] FiskFisk33@startrek.website 5 points 9 months ago

I am not good friends with js, what did I miss?

[-] mindbleach@sh.itjust.works 14 points 9 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.

[-] PoolloverNathan@programming.dev 5 points 9 months ago

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.

[-] mindbleach@sh.itjust.works 4 points 9 months ago

Yet the array contains exactly three nothings.

It's like a zen koan.

[-] cantstopthesignal@sh.itjust.works 2 points 9 months ago

Time is a flat circle

[-] Kindness@lemmy.ml 5 points 9 months ago

typeof(null) == 'object'

Because some people think planning an entirely new language should take less than 2 weeks. 10 days, in this case.

See wat for more.

[-] cantstopthesignal@sh.itjust.works 2 points 9 months ago

We wrote it wrong on purpose, as a joke.

[-] mindbleach@sh.itjust.works 1 points 9 months ago

The Wimp Lo doctrine is a valid theory for why JS is Like That.

If there's two ways to do something, JS picks all three.

[-] marcos@lemmy.world 7 points 9 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 2 points 9 months ago* (last edited 9 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

Not a JS dev either but ===.

Not really sure what the (+x) is about

[-] FiskFisk33@startrek.website 1 points 9 months ago

the remainder operator should return a number or a NaN right? do we actually need the triple here?

[-] marcos@lemmy.world 2 points 9 months ago* (last edited 9 months ago)

Not really. But with JS it's better safe than sorry.

The GP's addition is unnecessary, but I fully support anyone that decides to do it.

[-] FiskFisk33@startrek.website 2 points 9 months ago
[-] affiliate@lemmy.world 3 points 9 months ago
[-] marcos@lemmy.world 6 points 9 months ago
[-] affiliate@lemmy.world 9 points 9 months ago

what a wonderful and beautiful language. i’m so glad i asked

[-] ArtVandelay@lemmy.world 1 points 9 months ago

And so wonderfully similar to the way that symbol is used in other languages as well. Gosh darn it I love JavaScript

this post was submitted on 08 Mar 2024
475 points (98.2% liked)

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