onItemsEvents([callback], [remove])

Class: Tree.

Description:

Gets, registers or unregisters an event handler function for events triggered by adding, removing, updating items and when the Tree structure is changed.

Parameters:

Name	Type	Default	Description
`[callback]`	function		The event handler function. Receives an event object.
`[remove]`	boolean	false	Set to `true` to unregister the event handler.

Returns:

When called without parameters, an array of handler functions is returned, otherwise this Tree component is returned for method chaining.

Type: Array.<function()> | Tree

Examples:

Event object format:

Object {
    target: Tree,        // The component that triggered the event
    type: string,        // "add", "update", "remove", or "restructure".
    items: object[],     // Items effected by the action that triggered the event
    interactive: boolean // Only when type is "update". Indicates if the update was made by the user interacting with the item in GUI. `false` when updated programmatically.
}

Registering an event handler:

tree.onItemsEvents(e=>{alert(e.type);}); // shows the event type in a new message dialog window

Unregistering all registered event handlers:

let _handlers = tree.onItemsEvents(); // gets all handlers

for(let handler of _handlers) tree.onItemsEvents(handler, false); // unregisters each handler