code: function connStr(conn) {
    var conf = mergeDefaults(conn);
    var connString = conf.driver + '://' + conf.username + (conf.password ? ':' + conf.password : '') + '@' + conf.host
      + (conf.port ? ':' + conf.port : '') + '/' + conf.database;
    return connString;
  }
docs: Build a connection string from target db + env hash