jQuery - sort DIVs by className

Answer 1

jQuery abstracts the Array.prototype.sort() method so you can use it on wrapped sets:

var OrderDIV = function(asc) {
    $('div#list').children().detach().sort(function(a,b) {
        return asc ? (+a.textContent) - (+b.textContent) : (+b.textContent) - (+a.textContent);
    }).appendTo(document.body);
}

OrderDIV(0);

Demo: http://jsfiddle.et/Ls2kd/9/

For simplicity I ordered the <div> nodes by their content. If you need to use the ID it shouldn't be a problem at all. Just access a.id and strip out the part you need for comparison (regex for instance).

Another thing to mention, InternetExplorer isn't aware of .textContent therefore should it be a.textContent || a.text.

Answer 2

jQuery.fn.sortElements = (function(){

    var sort = [].sort;

    return function(comparator, getSortable) {

        getSortable = getSortable || function(){return this;};

        var placements = this.map(function(){

            var sortElement = getSortable.call(this),
                parentNode = sortElement.parentNode,

                // Since the element itself will change position, we have
                // to have some way of storing its original position in
                // the DOM. The easiest way is to have a 'flag' node:
                nextSibling = parentNode.insertBefore(
                    document.createTextNode(''),
                    sortElement.nextSibling
                );

            return function() {

                if (parentNode === this) {
                    throw new Error(
                        "You can't sort elements if any one is a descendant of another."
                    );
                }

                // Insert before flag:
                parentNode.insertBefore(this, nextSibling);
                // Remove flag:
                parentNode.removeChild(nextSibling);

            };

        });

        return sort.call(this, comparator).each(function(i){
            placements[i].call(getSortable.call(this));
        });

    };

})();

Use this sort criteria for your needs:

function sortCriteria(k) {
    var regex = /\b\d+/g;
    return function(a, b){
        return parseInt(a.id.match(regex)[k]) > parseInt(b.id.match(regex)[k]) ? 1 : -1;
    }
}

$("#list >").sortElements(sortCriteria(0));

Answer 3

You changed the requirements mid way ... just like a true client. Updated version with some comments attached. Just to confirm, there are two "configurable" variables at the front.

classPrefix: the "prefix" unique to the class used to determine sort order ('cat' in this case) listElementSelector: the jQuery selector used to obtain the list to sort.

function OrderDIV(position)
{
    var classPrefix = 'cat';
    var listElementSelector = '#list';

    // -- Decrement the position to make it 0 based
    position--;

    // -- Parses the "position" section from the given classes, and
    //    then the position at the specific index requested.
    var parsePosition = function(classes, pos) {
        // -- Split the "classes" into an array.
        var classList = classes.split(' ');

        // -- Determine which of the "classes" starts with the prefix we want.
        for( var i in classList )
        {
            if( classList[i].substr(0, classPrefix.length) == classPrefix )
            {
                // -- Strip out the positions section, and split it.
                var positions = classList[i].split('-')[1].split('.');

                // -- return the one position we want
                return positions[pos];
            }
        }

        // -- In the event that we don't find the class we're looking for ...
        return -1;
    }

    // -- Compares div A to div B, and returns an indicator of the order
    var funcSort = function(a, b) {
        // -- Use "parsePosition" to determine the sortable criteria from the classes.
       var compA = parsePosition($(a).attr('class'), position);
       var compB = parsePosition($(b).attr('class'), position);
       return (compA < compB) ? -1 : (compA > compB) ? 1 : 0;
    };

    // -- Select the list element.
    var list = $(listElementSelector);

    // -- Select the list items, and return them as an array.
    var listitems = list.children('div').get();

    // -- Sort the array using the "funcSort".
    listitems.sort(funcSort);

    // -- Go through each of the array entries, and "append" them to the list container
    //   (this moves them to the 'back' of the list)
    $.each(listitems, function(idx, itm) { list.append(itm); });
}