Select items and its sub items using values selected from a javascript based select menu in shiny

问题

Based on the question mentioned below. I would like to add dash in front of parent items and select subitems when select parent item. I tried shinytree and shinytreeview but I need a combo box not list, because list expands Using values selected from a javascript based select menu in shiny

来源：https://stackoverflow.com/questions/61797628/select-items-and-its-sub-items-using-values-selected-from-a-javascript-based-sel