nestedSortable jQuery plugin

nestedSortable is a jQuery plugin that extends jQuery Sortable UI functionalities to nested lists.
Note: Version 2.0 is published in branch '2.0alpha' and is available for testing. At the moment it has only been tested in Firefox and Chrome, if you work with IE feel free to give it a shot and let me know if something goes wrong.

What's new in version 2.0

The biggest change is that your nested list can now behave as a tree with expand/collapse funcionality. Simply set isTree to true in the options and you are good to go! Check the demo out to see what can be done with nestedSortable and a little CSS. (Note that all nestedSortable does is to assign/remove classes on the fly)
Also:

• isAllowed function finally works as expected, see the docs below
• Fixed: a small bug in the protectRoot function
• Changed: no drop zone will appear at all if you try to nest an item under another one that has the no-nesting class.
• Added: doNotClear option to prevent the plugin from deleting empty lists

Features

• Designed to work seamlessly with the nested set model (have a look at the toArray method)
• Items can be sorted in their own list, moved across the tree, or nested under other items.
• Sublists are created and deleted on the fly
• All jQuery Sortable options, events and methods are available
• It is possible to define elements that will not accept a new nested item/list and a maximum depth for nested items
• The root level can be protected
• The parentship of items can be locked, just as if it was a family tree.

Usage

<ol class="sortable">
	<li><div>Some content</div></li>
	<li>
		<div>Some content</div>
		<ol>
			<li><div>Some sub-item content</div></li>
			<li><div>Some sub-item content</div></li>
		</ol>
	</li>
	<li><div>Some content</div></li>
</ol>

	$(document).ready(function(){

		$('.sortable').nestedSortable({
			handle: 'div',
			items: 'li',
			toleranceElement: '> div'
		});

	});

Please note: every <li> must have either one or two direct children, the first one being a container element (such as <div> in the above example), and the (optional) second one being the nested list. The container element has to be set as the 'toleranceElement' in the options, and this, or one of its children, as the 'handle'.

Also, the default list type is <ol>.

This is the bare minimum to have a working nestedSortable. Check the demo out to see what can be accomplished with a little more.

Custom Options

disableParentChange (2.0)

Set this to true to lock the parentship of items. They can only be re-ordered within theire current parent container.

doNotClear (2.0)

Set this to true if you don't want empty lists to be removed. Default: false

expandOnHover (2.0)

How long (in ms) to wait before expanding a collapsed node (useful only if isTree: true). Default: 700

isAllowed (function)

You can specify a custom function to verify if a drop location is allowed. Default: function (placeholder, placeholderParent, currentItem) { return true; }

isTree (2.0)

Set this to true if you want to use the new tree functionality. Default: false

listType

The list type used (ordered or unordered). Default: ol

maxLevels

The maximum depth of nested items the list can accept. If set to '0' the levels are unlimited. Default: 0

protectRoot

Whether to protect the root level (i.e. root items can be sorted but not nested, sub-items cannot become root items). Default: false

rootID

The id given to the root element (set this to whatever suits your data structure). Default: null

rtl

Set this to true if you have a right-to-left page. Default: false

startCollapsed (2.0)

Set this to true if you want the plugin to collapse the tree on page load. Default: false

tabSize

How far right or left (in pixels) the item has to travel in order to be nested or to be sent outside its current list. Default: 20

excludeRoot

Exlude the root item from the toArray output

Custom Classes (you will set them in the options as well)

branchClass (2.0)

Given to all items that have children. Default: mjs-nestedSortable-branch

collapsedClass (2.0)

Given to branches that are collapsed. It will be switched to expandedClass when hovering for more then expandOnHover ms. Default: mjs-nestedSortable-collapsed

disableNestingClass

Given to items that will not accept children. Default: mjs-nestedSortable-no-nesting

errorClass

Given to the placeholder in case of error. Default: mjs-nestedSortable-error

expandedClass (2.0)

Given to branches that are expanded. Default: mjs-nestedSortable-expanded

hoveringClass (2.0)

Given to collapsed branches when dragging an item over them. Default: mjs-nestedSortable-hovering

leafClass (2.0)

Given to items that do not have children. Default: mjs-nestedSortable-leaf

disabledClass (2.0)

Given to items that should be skipped when sorting over them. For example, non-visible items that are still part of the list. Default: mjs-nestedSortable-disabled

Custom Methods

serialize

Serializes the nested list into a string like setName[item1Id]=parentId&setName[item2Id]=parentId, reading from each item's id formatted as 'setName_itemId' (where itemId is a number). It accepts the same options as the original Sortable method (key, attribute and expression).

toArray

Builds an array where each element is in the form:

setName[n] =>
{
	'item_id': itemId,
	'parent_id': parentId,
	'depth': depth,
	'left': left,
	'right': right,
}

It accepts the same options as the original Sortable method (attribute and expression) plus the custom startDepthCount, that sets the starting depth number (default is 0).

toHierarchy

Builds a hierarchical object in the form:

'0' ...
	'id' => itemId
'1' ...
	'id' => itemId
	'children' ...
		'0' ...
			'id' => itemId
		'1' ...
			'id' => itemId
'2' ...
	'id' => itemId

Similarly to toArray, it accepts attribute and expression options.

Events

change

Fires when the item is dragged to a new location. This triggers for each location it is dragged into not just the ending location.

sort

Fires when the item is dragged.

revert

Fires once the object has moved if the new location is invalid.

relocate

Only fires once when the item is done bing moved at its final location.

Known Bugs

nestedSortable doesn't work properly with connected draggables, because of the way Draggable simulates Sortable mouseStart and mouseStop events. This bug might or might not be fixed some time in the future (it's not specific to this plugin).

Requirements

jQuery UI Sortable 1.10+ (might work with 1.9, but not tested)

Browser Compatibility

Tested with: Firefox, Chrome
NOTE: This is still an alpha version, please test thoroughly in whichever version of IE you target

License

This work is licensed under the MIT License.
Which means you can do pretty much whatever you want with it.