code: function checknick(next) {
          if (args.nick) {
            userent.list$({ nick: args.nick }, function(err, users) {
              if (err) return done(err, { ok: false, user: user })
              for (var i = 0; i < users.length; i++) {
                var each = users[i]
                if (each.id !== user.id) {
                  return done(null, {
                    ok: false,
                    why: 'nick-exists',
                    nick: args.nick
                  })
                }
              }
  
              next()
            })
            return
          }
          next()
        }
docs: unsafe nick unique check, data store should also enforce !!