isSurrogatePair

Checks if the specified high and low chars are Char.isHighSurrogate and Char.isLowSurrogate correspondingly.

@ExperimentalNativeApiactual fun Char.Companion.isSurrogatePair(high: Char, low: Char): Boolean(source)

import kotlin.text.Char

fun main() {
    val high = '\uD83D'   // high surrogate for 😀
    val low  = '\uDE00'   // low surrogate for 😀

    val isPair = Char.isSurrogatePair(high, low)

    println("Is the pair a surrogate pair? $isPair") // true
}

Source