Get an rgb() array of any hex or rgb color.

rgb-array.js

(function() {
    function getRgbArray(color, alpha) {
        // Always return an array, either empty or filled.
        var rgb = [];
        var hex;

        // Get an array of rgb(a) values.
        if (color.substr(0, 1) === '#') {
            /* HEX STRING */
            // If the first character is # we're dealing with a hex string. Get
            // an array of each character. This is more explicit than dealing
            // with the indices of a String object due to all other instances
            // of hex in this function.
            hex = color.substr(1).split('');
            if (hex.length === 3) {
                // If this is a 3-char color, e.g. #f00, make it 6 characters
                // by duplicating each one.
                hex = [hex[0], hex[0], hex[1], hex[1], hex[2], hex[2]];
            }
            if (hex.length === 6) {
                // Only deal with 6-char hex colors when computing the rgb
                // array. Anything else at this point has been passed
                // incorrectly.
                var i = 0;
                var x = 0;
                var hexStr;
                // Convert each hex pair (represented by hexStr) into a decimal
                // value to go in rgb[]. i is the rgb[] index whilst x is 2i,
                // which translates Array(3) to Array(6).
                while (i < 3) {
                    hexStr = hex[x] + hex[x + 1];
                    rgb[i] = parseInt(hexStr, 16);
                    i += 1;
                    x = i * 2;
                }
            }
        } else if (color.search(/rgb/) !== -1) {
            /* RGB(A) STRING */
            rgb = color.match(/([0-9]+\.?[0-9]*)/g);
        }

        // Add or remove the alpha value.
        if (alpha && rgb.length === 3) {
            // If an alpha value has been requested and there currently isn't
            // one, add 1 as the alpha value.
            rgb.push(1);
        } else if (! alpha && rgb.length === 4) {
            // Otherwise if there's an alpha value that hasn't been requested,
            // remove it.
            rgb.pop();
        }

        // Ensure all values in rgb are decimal numbers, not strings.
        for (var i = 0; i < rgb.length; i++) {
            rgb[i] = parseInt(rgb[i], 10);
        }

        return rgb;
    }

    // Demonstrate.
    var colors = [
        '#fff0ff',
        '#f0f',
        'rgb(0,255,50)',
        'rgb(0,   255,50)',
        'rgba(0,255,50 , 1)'
    ];
    for (var i = 0; i < colors.length; i++) {
        console.log('no alpha', colors[i], getRgbArray(colors[i], false));
        console.log('with alpha', colors[i], getRgbArray(colors[i], true));
    }
})();