asArray

Converts the result of RegExp.exec to an array where the first element contains the entire matched text and each subsequent element is the text matched by each capturing parenthesis.

inline fun RegExpMatch.asArray(): Array<out String?>(source)

import kotlin.js.RegExp

fun main() {
    val regex = RegExp("(\\w+)\\s(\\w+)")
    val text   = "Hello world"

    val match = regex.exec(text)           // RegExpMatch?
    val parts = match?.asArray()           // Array<out String?>

    println(parts?.joinToString(separator = ", "))  // prints: Hello world, Hello, world
}

Source