code: function (hue, saturation, value, alpha) {
        alpha = /%/.test(alpha)
          ? parseInt(alpha, 10) / 100
          : parseFloat(alpha, 10);
  
        alpha = String(alpha).replace(/^0+\./, '.');
  
        var rgb = hsb2rgb(hue, saturation, value);
        return 'rgba(' + rgb.join(', ') + ', ' + alpha + ')';
      }
docs: Converts HSV (HSB) color values with alpha specified to RGBa.
  Saturation, brightness and alpha can be expressed as floats or
  percentages.
  
  color: hsba(220, 45%, .3, .4);
  color: hsba(220deg, 0.45, 30%, 40%);