moz-rewrite block referer for Twitter external domains

[
    {
        "url" : /^.*$/, // if request going to any domain
        "headers" : function() {
            var headers = {};
            // block referer for request coming from any domain except twitter.com
            if (request.window_location.host != "twitter.com")
            {
                headers = {
                    "Referer" : null
                };
            }
            return headers;
        }
    },
    {
        "url" : /^(?!https:\/\/twitter.com\/).*$/, // if request going to other domain than twitter.com
        "headers" : function() {
            var headers = {};
            if (request.window_location.host == "twitter.com") // block referer for request coming from twitter.com
            {
                headers = {
                    "Referer" : null
                };
            }
            return headers;
        }
    }
]