How to create a collapsing tree table in html/css/js?

Question

I have some data to display that is both tabular and hierarchical. I'd like to let the user be able to expand and collapse the nodes.

Sort of like this, except functional:

http://www.maxdesign.com.au/articles/tree-table/

What would be the best way to approach this? I'm not adverse to using an off-the-shelf plugin.

Answer 1

SlickGrid has this functionality, see the tree demo.

If you want to build your own, here is an example (jsFiddle demo): Build your table with a data-depth attribute to indicate the depth of the item in the tree (the levelX CSS classes are just for styling indentation): 

<table id="mytable">
    <tr data-depth="0" class="collapse level0">
        <td><span class="toggle collapse"></span>Item 1</td>
        <td>123</td>
    </tr>
    <tr data-depth="1" class="collapse level1">
        <td><span class="toggle"></span>Item 2</td>
        <td>123</td>
    </tr>
</table>

Then when a toggle link is clicked, use Javascript to hide all <tr> elements until a <tr> of equal or less depth is found (excluding those already collapsed):

$(function() {
    $('#mytable').on('click', '.toggle', function () {
        //Gets all <tr>'s  of greater depth below element in the table
        var findChildren = function (tr) {
            var depth = tr.data('depth');
            return tr.nextUntil($('tr').filter(function () {
                return $(this).data('depth') <= depth;
            }));
        };

        var el = $(this);
        var tr = el.closest('tr'); //Get <tr> parent of toggle button
        var children = findChildren(tr);

        //Remove already collapsed nodes from children so that we don't
        //make them visible. 
        //(Confused? Remove this code and close Item 2, close Item 1 
        //then open Item 1 again, then you will understand)
        var subnodes = children.filter('.expand');
        subnodes.each(function () {
            var subnode = $(this);
            var subnodeChildren = findChildren(subnode);
            children = children.not(subnodeChildren);
        });

        //Change icon and hide/show children
        if (tr.hasClass('collapse')) {
            tr.removeClass('collapse').addClass('expand');
            children.hide();
        } else {
            tr.removeClass('expand').addClass('collapse');
            children.show();
        }
        return children;
    });
});