The README says the tableName is optional and the code uses a '*' if no tableName is given. But if you don't pass one, you get this error as data in the callback (not as a proper error):
Error: Unknown table for BitMEX subscription: *. Available tables are announcement,connected,chat,publicNotifications,instrument,settlement,funding,insurance,liquidation,orderBookL2,orderBook10,quote,trade,quoteBin1m,quoteBin5m,quoteBin1h,quoteBin1d,tradeBin1m,tradeBin5m,tradeBin1h,tradeBin1d,privateNotifications,account,wallet,affiliate,margin,position,transact,order,execution.
client.addStream('XBTUSD', data => {
console.log(data);
});