Get parameter names from a function

Extract parameter names

//+ fn -> [a]
var getParameterNames = (function () {
    var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg,
        ARGUMENT_NAMES = /([^\s,]+)/g;

    return function (fn) {
        var fnStr = fn.toString().replace(STRIP_COMMENTS, ''),
            names = fnStr.slice(fnStr.indexOf('(')+1, fnStr.indexOf(')')).match(ARGUMENT_NAMES);

        return names || [];
    };
})();

function add (x, y) {
    return x + y;
}

console.log(getParameterNames(add));    // => ['x', 'y']

To anyone who finds this and find it useful; be aware that uglifying the code will completely wreck it.