JavaScrip hex color mix function

mix.js

const mix = (hex1, hex2, percent) => {
  const breakup = (hex) => hex.match(/[a-f0-d]{2}/ig).map(n => parseInt(n, 16));
  const rgb1 = breakup(hex1);
  const rgb2 = breakup(hex2);
  const mixed = rgb1.map((c, i) => Math.round((c * (1 - percent)) + (rgb2[i] * percent)).toString(16));
  return '#'+mixed.map(s => s.length < 2 ? '0'+s : s).join('');
};
console.log(mix('#000000','#ffffff', .2));