I want onSnapshot to fail if there is a failed internet connection (getting user record – if none is found I set up a new one).

I see

onSnapshot(doc(db, 'users', userAuthData.authUser.uid), 
{ source:'cache'},
(returndoc) =>{...})

but when I change 'cache' to 'server' I get no overload matches this call

Any advice? Source for options documentation?