$(function() {
    var searchParams = new URLSearchParams(location.search);
    var anchor = searchParams.get('anchor');
    if (!anchor) {
        throw new TypeError('There is no "anchor" parameter in the URL');
    }
    openCollapse(anchor).done(function () {
        var element =  document.getElementById(anchor);
        element.scrollIntoView({
            behavior: 'smooth',
            block: 'start'
        });
        console.log('It worked on main function');
    });
});

function openCollapse (elementId) {
    var promises = [];
    var targetCollapse = $('#' + elementId);
    if (!targetCollapse.hasClass('collapse')) {
        throw new TypeError('error');
    }
    var parents = targetCollapse.parents('.panel-collapse').toArray().reverse();
    parents.push(targetCollapse[0]);

    $.each(parents, function (key, object) {
        var dfd = new $.Deferred();
        $(object).collapse('show');
        $(object).on('shown.bs.collapse', function () {
            dfd.resolve();
        });
        promises.push(dfd);
    });

    return $.when.apply($, promises).promise();
}