Hi Prashant, sorry for your challenge I believe there is a gap in our documentation thank you for pointing it out.
Instead of calling api.selectionSet.add(NODE_ID) can you please try: api.selectionSet.set(NODE_ID) or api.selectionSet.add(NODE_ID) and see if that is giving you the results you want? I believe IDs are what will create the selection. I am investigating with our team to confirm.