Integer to Roman Numerals

numerals.js

function numeral(num) {
    const ones = ['', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX'];
    const tens = ['', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX', 'XC'];
    const huns = ['', 'C', 'CC', 'CCC', 'CD', 'D', 'DC', 'DCC', 'DCCC', 'CM'];
    return [
        'X̅'.repeat(Math.floor(num/10000)),
        'M'.repeat(Math.floor((num%10000)/1000)),
        huns[Math.floor((num%1000)/100)],
        tens[Math.floor(((num%1000)%100)/10)],
        ones[Math.floor(((num%1000)%100)%10)]
    ].join('');
};

console.log(numeral(12345)); // X̅MMCCCXLV