title: will redis delete my old express.js sessions?
body: <p>i'm using redis as my session store for a node.js + express app...will it automatically delete old sessions after they expire?</p>
  
  <p>...or do I need to do some cleanup on the server side? (so the db doesn't grow too large)</p>
  
  <pre><code>  var RedisStore = require('connect-redis')(express)
  
    app.use(express.session({
      store: new RedisStore({
        host: cfg.redis.host,
        db: cfg.redis.db
      }), 
      secret: 'foobar'
    }));
  </code></pre>