Can anyone explain why long math is extremely slow...

# javascript

[Luca]

Can anyone explain why long math is extremely slow compared in JS compared to same code but replacing all Long/LongArrays with Double/DoubleArrays?

[ephemient]

JS does not have 64-bit integers, so Kotlin/JS has to emulate them

[ephemient]

e.g. https://github.com/JetBrains/kotlin/blob/master/libraries/stdlib/js-v1/src/js/long.js

[Luca]

@ephemient I see. So is using Doubles the only easy semi-workaround? Would using BigInt on the js target perform better that kotlin Long?

[ephemient]

BigInt aren't easily accessible from Kotlin/JS because they're a newer language feature while Kotlin still targets ES5 (e.g. https://youtrack.jetbrains.com/issue/KT-48980/KJS-Use-of-BigInt-leads-to-JsParserException-what-makes-it-unusable)

[ephemient]

and if you're only working with Long-sized emulation, BigInt is likely to be slower because of the overhead of handling arbitrary sizes

[ephemient]

all the other primitive numeric types, including Double, map to JS Number

[ephemient]

so that's as "native" as it gets

[Luca]

That makes sense. Thanks for the info.

[Luca]

Now if js would just die… and web would use a language that isn’t terrible, my life would be a lot easier lol…

[CLOVIS]

While we're on this subject, do you know where intArrayOf etc are declared in JS?

[ephemient]

Array constructors are hard-wired in the compiler on all platforms