gistfile1.js

var tuiter = require('tuiter')(keys);

var getTweets = function(screen_name, max_id) {

  tuiter.userTimeline({screen_name: screen_name, max_id: max_id}, function(err, tweets){
    //save tweets

    //get more
    if(tweets.length)
      getTweets(screen_name, tweets[tweets.length - 1].id - 1);
  });
};

getTweets('username');