Function charLengthAt

lib/internal/readline/utils.js:50–57

(str, i)

}

function charLengthAt(str, i) {
  if (str.length <= i) {
    // Pretend to move to the right. This is necessary to autocomplete while
    // moving to the right.
    return 1;
  }
  return StringPrototypeCodePointAt(str, i) >= kUTF16SurrogateThreshold ? 2 : 1;
}

/*
  Some patterns seen in terminal key escape codes, derived from combos seen