Converting an RGB Color To Hex With JavaScript

function colorToHex(color) {
   if (color.substr(0, 1) === '#') {
       return color;
   }
   var digits = /(.*?)rgb\((\d+), (\d+), (\d+)\)/.exec(color);
  
   var red = parseInt(digits[2]);
   var green = parseInt(digits[3]);
   var blue = parseInt(digits[4]);
  
   var rgb = blue | (green << 8) | (red << 16);
   return digits[1] + '#' + rgb.toString(16);
};

Now, I can compare colors like so.

equals(colorToHex('rgb(120, 120, 240)'), '#7878f0');