StringOps that handle surrogate pair.

CodePointOps.scala

implicit class CodePointOps(val self: String) extends AnyVal {

  // take
  def takeCodePoints(n: Int): String = {
    val itr = java.text.BreakIterator.getCharacterInstance

    itr.setText(self)

    val codePointCount = Iterator.continually(itr.next()).takeWhile(_ != java.text.BreakIterator.DONE).take(n).size

    new String(self.codePoints.toArray, 0, codePointCount)
  }
}

// example
"𠀋𡑮".takeCodePoints(1) // => "𠀋"