DnD and Sorting of tree nodes

[simoami]

Awesome component! It would be great if it supported drag and drop operations to either sort tree nodes or drop into a different pattern. Since everyone has a different use case, a handler canDrop(node: Node, newParent: Node, oldParent: Node) -> Boolean where the default handler returns true all the time. Here's what the new API could look like:

node props:

draggable: {Boolean | Function} - function if behavior is dynamic. E.g. disabled node can't be dragged
dragGroup: {String} - allows for nodes to only interact with their own types

tree props:

dragNodes: {Boolean} - enables drag & drop behavior
sortable: {Boolean} - enables sorting behavior with nodes on the same dragGroup
canDrop(node: Node, newParent: Node, oldParent: Node) -> Boolean
didDrop(node: Node, newParent: Node, oldParent: Node, position: Number) -> void - position is relevant when sortable is on and the node is dropped into a specific position inside a parent node