integer to roman

import java.util.TreeMap;

public class RomanNumber {

    private final static TreeMap<Integer, String> map = new TreeMap<Integer, String>();

    static {

        map.put(1000, "M");
        map.put(900, "CM");
        map.put(500, "D");
        map.put(400, "CD");
        map.put(100, "C");
        map.put(90, "XC");
        map.put(50, "L");
        map.put(40, "XL");
        map.put(10, "X");
        map.put(9, "IX");
        map.put(5, "V");
        map.put(4, "IV");
        map.put(1, "I");

    }

    public final static String toRoman(int number) {
        int l =  map.floorKey(number);
        if ( number == l ) {
            return map.get(number);
        }
        return map.get(l) + toRoman(number-l);
    }

}

function integer_to_roman(num) {
  if (typeof num !== "number") return false;

  var digits = String(+num).split("");

  key = [
    "",
    "C",
    "CC",
    "CCC",
    "CD",
    "D",
    "DC",
    "DCC",
    "DCCC",
    "CM",
    "",
    "X",
    "XX",
    "XXX",
    "XL",
    "L",
    "LX",
    "LXX",
    "LXXX",
    "XC",
    "",
    "I",
    "II",
    "III",
    "IV",
    "V",
    "VI",
    "VII",
    "VIII",
    "IX",
  ];

  roman_num = "";

  i = 3;

  while (i--) roman_num = (key[+digits.pop() + i * 10] || "") + roman_num;

  return Array(+digits.join("") + 1).join("M") + roman_num;
}

console.log(integer_to_roman(888666687));