color-string-to-hex.js

function colorStringToHex (color) {
    if (color.substr(0, 1) === '#') {
        return color;
    }
    var digits = /(.*?)rgb\((\d+), (\d+), (\d+)\)/.exec(color);
    
    var red = parseInt(digits[2], 10);
    var green = parseInt(digits[3], 10);
    var blue = parseInt(digits[4], 10);
    
    var rgb = blue | (green << 8) | (red << 16);
    return digits[1] + '#' + rgb.toString(16);
}