Understanding how to respond to user actions is crucial when building interactive drag-and-drop interfaces. SortableJS provides several key events that let you hook into the drag-and-drop lifecycle and trigger custom logic as users interact with your lists or boards. The most commonly used events include onStart, onEnd, onAdd, onRemove, and onUpdate.

The onStart event fires when a user begins dragging an item. This is where you might highlight the dragged element or prepare the UI for a drag operation. The onEnd event triggers when the drag operation finishes, regardless of whether the item was moved to a new location or returned to its original spot. You can use this event to remove visual highlights or perform cleanup.

When items move between connected lists, onAdd and onRemove become important. The onAdd event is called when an item is dropped into a new list, allowing you to update data or trigger animations. The onRemove event fires when an item leaves its original list, which is useful for updating the source list or handling empty states.

Finally, the onUpdate event is triggered whenever the order of items within a single list changes, such as when a user reorders tasks in a Kanban column. This event is ideal for syncing the new order with your data model or saving changes.

To see these events in action, you can attach event listeners to a sortable list and log each event to the console as users interact with it.