https://android.benigumo.com/20230529/kotlin-unicode/

dump.kt

fun dump(data: String) {
    println(data)

    val ss = Regex("\\X").findAll(data)
      .map { match -> match.value }
      .toList()

    println(ss)
    println(ss.size)
    println()

    ss.forEach { s ->
      println("$s ${s.toUtf16EscapeSequence()}")
      s.codePoints().forEach { cp ->
        val hcp = "0x%X".format(cp)
        val c = Character.toChars(cp).joinToString("")
        println(" ${cp.toUtf16EscapeSequence()} $hcp ($c)")
      }
    }
  }

extensions.kt

fun String.toUtf16EscapeSequence(): String {
  // String.chars() returns IntStream under 0x10000 Int only,
  // no need to consider utf-16 surrogate pair
  return this.chars()
    .asSequence()
    .joinToString("") { i -> "\\u%04X".format(i) }
}

fun Int.toUtf16EscapeSequence(): String {
  val cp = this // code point
  return Character.toChars(cp).joinToString("")
    .toUtf16EscapeSequence()
}

【Kotlin】絵文字を含む Unicode 文字列の文字数をカウントする方法と文字ごとの構成
👉 https://android.benigumo.com/20230529/kotlin-unicode/