Mini sort table with jquery

sortable.js

function sortable(table_dom, column_types, default_ordering) {
    var rows = $(table_dom).find('tbody tr')
    var dataset = [];

    for (var i = 0; i < rows.length; ++i) {
        var vals = $(rows[i]).find('td').toArray().map(function(v){
            // console.log(arguments);
            return v.innerText; 
        });
        dataset.push(vals);
    }
    
    function make_comparator(offset, column_type, ordering) {
        switch(column_type) {
            case 'n' :
                if(ordering == 'asc') {
                    return function(x, y) { 
                        return x[offset] - y[offset]; 
                    }
                } else {
                    return function(x, y) { 
                        return y[offset] - x[offset]; 
                    }
                }
                break;
            case 's':
                if(ordering == 'asc') {
                    return function(x,y) {
                        if(x[offset] > y[offset]) return 1;
                        if(x[offset] < y[offset]) return -1;
                        return 0;
                    }
                } else {
                    return function(x,y) {
                        if(x[offset] > y[offset]) return -1;
                        if(x[offset] < y[offset]) return 1;
                        return 0;
                    }
                }
                break;
        }
    }
    
    function populate() {
        $(table_dom).find('tbody tr').each(function(row_index, row){
            $(row).find('td').each(function(col_index, cell) {
                $(cell).text(dataset[row_index][col_index]);
            });
        });
    }
    
    var ordering_ = { a: 'asc', d: 'desc' };
    
    function make_sort_by(index, ele) {
        return $(ele).click(function(){
            var col = $(this);
            var ord_orig = col.attr('data-sort-order') ;
            var ord_new;
            if ( ord_orig ) {
                ord_new = (ord_orig == 'asc') ? 'desc' : 'asc';
                dataset.reverse();
            } else {
                ord_new = ordering_[default_ordering[index]];
                // clear other columns' data-sort-order attrib
                col.parent().find('th').not(col).removeAttr('data-sort-order');
                // sort table
                dataset.sort(make_comparator(index, column_types[index], ord_new));
            }
            col.attr('data-sort-order', ord_new);
            populate();
        });
    };
    return $(table_dom).find('thead th').map(make_sort_by);
}

sortable('table', 'nss', 'daa');