type RGB = {
  r: number;
  g: number;
  b: number;
};

export default (hex: string): RGB | null => {
  const shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
  const longHex = hex.replace(shorthandRegex, (m: string, r: string, g: string, b: string) => r + r + g + g + b + b);
  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(longHex);

  return result ? {
    r: parseInt(result[1], 16),
    g: parseInt(result[2], 16),
    b: parseInt(result[3], 16),
  } : null;
};