mudlet = mudlet or {}; mudlet.mapper_script = true
local okayExits = { -- <- this list is new (i just lazily did it like this so i could 'okayExits[dir]' instead of having to iterate to see if value is in list)
  nw = true, ne = true, sw = true, se = true, s = true, n = true, e = true, w = true,
  northwest = true, northeast = true, southwest = true, southeast = true,
  south = true, north = true, east = true, west = true,
  up = true, u = true, down = true, d = true
}
function createroom()
-- ...

function exits(roomid)
-- ...
  -- Scrub through exits
  for dir, hash in pairs(roomexits) do
    exitroom = getRoomIDbyHash(hash)
    if (okayExits[dir]) then  -- <- new
-- ...
    end -- <- new
  end
end