This post describes how to make a condensation free bathroom mirror using an automatic mirror heater. See the one I made in 2007 here. Look carefully and you will notice the condensation around the edge but not in the central heated area.
Without a heater it would be impossible to use the mirror without first wiping it with a towel. Cold mirrors usually mist over again after wiping.
With an active mirror heater it’s possible to get straight out of a bath or shower and use the mirror immediately.