Function Control.canDropData

Godot calls this method to test if data from a control's getDragData can be dropped at position. position is local to this control. This method should only be used to test the data. Process the data in dropData.

bool canDropData(VariantArg1) (
  in Vector2 position,
  in VariantArg1 data
);

func can_drop_data(position, data): # Check position if it is relevant to you # Otherwise, just check data return typeof(data) == TYPE_DICTIONARY and data.has("expected")