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How can I make this regex work on Kotlin/JS the same way it works on Kotlin/JVM?

```fun main() {
	val r = Regex("""\h+([^:\v]+):""")
    println(r.matchEntire("   Version:")?.groupValues)
    // JVM: [   Version:, Version]
    // JS: SyntaxError: Invalid regular expression: /\h+([^:\v]+):/gu: Invalid escape
}```
<https://pl.kotl.in/HwXS2Fv3u>

EDIT: Ahh, never mind. `\h` (horizontal whitespace) doesn’t exist in JS. I’ll try replacing it with

```[\t\x{00A0}\x{1680}\x{180E}\x{2000}\x{2001}\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}\x{200A}\x{202F}\x{205F}\x{3000}]```

(as found on <https://regex101.com/>)

further suggestions are welcome!

<https://stackoverflow.com/a/45046733|SO suggests> `[^\S\r\n]+` to replace `\h`

An excellent resource when it comes to regex is <https://www.regular-expressions.info/>.
You can for example easily compare the features of different dialects in the reference.
On <https://www.regular-expressions.info/refshorthand.html> you would find the `\h` and see that Java from version 8 on supports it while JavaScript does not.
And on <https://www.regular-expressions.info/shorthand.html#more> you sould then have a elaborate description and alternatives, so the replacement should be `*[*\t\p{Zs}*]`. Unfortunately `\p...` is POSIX class which is also not supported by JavaScript.* :disappointed:

*But on* <https://www.compart.com/de/unicode/category/Zs> you can see which characters are part of `Zs`, so your replacement is almost correct, you just miss space and have additionally the "Mongolian Vowel Separator" which is not part of `Zs`.

ooooh, thank you Björn! I didn't know there was so much to read on this website. It's good to know for later

thanks <@U0152P3VB5J>, that helps. Unfortunately I’m getting tangled up in other regex differences… it seems like `[^\v]` doesn’t work consistently

Of course, `\v` is as little supported in JS as `\h`.
`[^\v]` probably means either "not a `v`" or "neither `v` nor a backslash"

<https://www.regular-expressions.info/shorthand.html#more> is your friend again

sure would be nice if Kotlin had a common implementation of a Regex engine, so it was the same on all platforms

<https://youtrack.jetbrains.com/issue/KT-49557>

image.png

well…. PCRE is written in C. So that could be called from Java and Native, and maybe from JS using wasm?