Learning jQuery 3 - Fifth Edition

Alternating sort directions

Our final sorting enhancement is to allow for both ascending and descending sort orders. When the user clicks on a column that is already sorted, we want to reverse the current sort order.

To reverse a sort, all we have to do is to invert the values returned by our comparator. We can do this with a simple direction argument to the sort comparator:

const comparator = (a, b, direction = 1) =>  a < b ?    -direction :    (a > b ? direction : 0);

If direction equals 1, then the sort will be the same as before. If it equals -1, the sort will be reversed. By combining this concept with some classes to keep track of the current sort order of a column, achieving alternating sort directions is simple:

// ....on('click', (e) ...