[MyNameIsCode]

Привет, гуру js программирования!
Как можно сократить этот код? )

$(document).ready(function() {
    var url_string = window.location.href;
    function get_params_string() {
        var arr = url_string.split('?');
        var get_params = null;
        if (url_string.length > 1 && arr[1] !== '') {
            get_params = arr[1];
        }
        return get_params;
    }

    var url = new URL(url_string);

    var sort_params = [
        url.searchParams.get("start-date-sort"),
        url.searchParams.get("end-date-sort"),
        url.searchParams.get("start-sum-sort"),
        url.searchParams.get("end-sum-sort")
    ];
    console.log(get_params_string());
    if (get_params_string() === undefined || get_params_string() === null) {
        $('#start-date-sort').attr("href","?start-date-sort=DESC");
        $('#end-date-sort').attr("href","?end-date-sort=DESC");
        $('#start-sum-sort').attr("href","?start-sum-sort=DESC");
        $('#end-sum-sort').attr("href","?start-date-sort=DESC");
    } else {
        re = /[a-z-]*-sort=(desc|asc)/gi;
        str = get_params_string().replace(re, '');
        if (sort_params[0] !== null) {
            if (sort_params[0] === 'DESC') {
                $('#start-date-sort').attr("href",'?'+str+'&start-date-sort=ASC');
            } else if (sort_params[0] === 'ASC') {
                $('#start-date-sort').attr("href",'?'+str+'&start-date-sort=DESC');
            }
        } else if (sort_params[0] === null || sort_params[0] === undefined) {
            $('#start-date-sort').attr("href",'?'+str+'&start-date-sort=DESC');
        }

        if (sort_params[1] !== null) {
            if (sort_params[1] === 'DESC') {
                $('#end-date-sort').attr("href",'?'+str+'&end-date-sort=ASC');
            } else if (sort_params[1] === 'ASC') {
                $('#end-date-sort').attr("href",'?'+str+'&end-date-sort=DESC');
            }
        } else if (sort_params[1] === null || sort_params[1] === undefined) {
            $('#end-date-sort').attr("href",'?'+str+'&end-date-sort=DESC');
        }

        if (sort_params[2] !== null) {
            if (sort_params[2] === 'DESC') {
                $('#start-sum-sort').attr("href",'?'+str+'&start-sum-sort=ASC');
            } else if (sort_params[2] === 'ASC') {
                $('#start-sum-sort').attr("href",'?'+str+'&start-sum-sort=DESC');
            }
        } else if (sort_params[2] === null || sort_params[2] === undefined) {
            $('#start-sum-sort').attr("href",'?'+str+'&start-sum-sort=DESC');
        }

        if (sort_params[3] !== null) {
            if (sort_params[3] === 'DESC') {
                $('#end-sum-sort').attr("href",'?'+str+'&end-sum-sort=ASC');
            } else if (sort_params[3] === 'ASC') {
                $('#end-sum-sort').attr("href",'?'+str+'&end-sum-sort=DESC');
            }
        } else if (sort_params[3] === null || sort_params[3] === undefined) {
            $('#end-sum-sort').attr("href",'?'+str+'&end-sum-sort=DESC');
        }
    }
});