We have one small problem at this point. As time goes on, more and more rooms will be created and more messages will accumulate. Eventually, we will run Redis out of memory. We are not being good Redis citizens. We need to remove our Redis data and will do this with a new worker.

Create a file named chat.js under the workers directory. Start the function with the following code:

var client = require('../redis').client,
  log = require('../middleware/log');

var delta = 60 * 60 * 1000 * 3; //10800000
var interval = 60 * 60 * 1000 * 2; //7200000

We include our Redis client and logger. Then, we set up our delta and interval. We will remove any room, chat, or user that has been inactive or was created 3 hours ago (10,800,000 milliseconds ago). We will do this check every 2 hours (7,200,000 milliseconds). If we wanted, we could even make these values part of the config, so it could be configurable on each launch. Now, let's create the room check, as shown in the following code...