var  position = exchange.IO("api", "GET","/fapi/v2/positionRisk","timestamp="+Date.now()+"&symbol="+sym+"USDT")
     var trades = exchange.IO("api", "GET","/fapi/v1/trades","limit=200&timestamp="+Date.now()+"&symbol="+sym+"USDT")//获取最近成交
   var depth = exchange.IO("IO", "api", "GET","/fapi/v1/depth","timestamp="+Date.now()+"&symbol="+sym+"USDT")//获取深度

Postion y trades obtienen valores, ¿por qué la profundidad está vacía?