db.adminCommand( { replSetGetStatus : 1 } )

{
    ...
    "date" : ISODate("2018-12-17T10:39:00.247Z"),
    "myState" : 1,
    ...
}

{
    ...
    "date" : ISODate("2018-12-17T10:39:00.247Z"),
    "myState" : 2,
    ...
}