The DataTransfer.clearData() method removes the drag operation's drag data for the given type. If data for the given type does not exist, this method does nothing.

API clearData DataTransfer drag and drop HTML DOM Method Reference

The DataTransfer object is used to hold the data that is being dragged during a drag and drop operation. It may hold one or more data items, each of one or more data types. For more information about drag and drop, see HTML Drag and Drop API.

API DataTransfer drag and drop HTML Drag and Drop API Interface NeedsMarkupWork Reference Web Development