Javascript: parse string to object (underscore)

Javascript: parse string to object

// string: one=1&two=2&three=3
// result: Object {one: 1, two: 2, three: 3};

// see: underscorejs.org

parseQueryString: function (queryString) {
    var params = {};
    if(queryString){
        _.each(
            _.map(decodeURI(queryString).split(/&/g),function(el,i){
                var aux = el.split('='), o = {};
                if(aux.length >= 1){
                    var val = undefined;
                    if(aux.length == 2)
                        val = aux[1];
                    o[aux[0]] = val;
                }
                return o;
            }),
            function(o){
                _.extend(params,o);
            }
        );
    }
    return params;
},