Twitter bot using node.js and twit module to retweet interesting info of node.js

bot.js

//
//  Bot
//  class for performing various twitter actions
//
var Twit = require('../lib/twitter');

var Bot = module.exports = function(config) { 
  this.twit = new Twit(config);
};

//
//  post a tweet
//
Bot.prototype.tweet = function (status, callback) {
  if(typeof status !== 'string') {
    return callback(new Error('tweet must be of type String'));
  } else if(status.length > 140) {
    return callback(new Error('tweet is too long: ' + status.length));
  }
  this.twit.post('statuses/update', { status: status }, callback);
};

//
//  choose a random friend of one of your followers, and follow that user
//
Bot.prototype.mingle = function (callback) {
  var self = this;
  
  this.twit.get('followers/ids', function(err, reply) {
      if(err) { return callback(err); }
      
      var followers = reply.ids
        , randFollower  = randIndex(followers);
        
      self.twit.get('friends/ids', { user_id: randFollower }, function(err, reply) {
          if(err) { return callback(err); }
          
          var friends = reply.ids
            , target  = randIndex(friends);
            
          self.twit.post('friendships/create', { id: target }, callback); 
        })
    })
};

//
//  prune your followers list; unfollow a friend that hasn't followed you back
//
Bot.prototype.prune = function (callback) {
  var self = this;
  
  this.twit.get('followers/ids', function(err, reply) {
      if(err) return callback(err);
      
      var followers = reply.ids;
      
      self.twit.get('friends/ids', function(err, reply) {
          if(err) return callback(err);
          
          var friends = reply.ids
            , pruned = false;
          
          while(!pruned) {
            var target = randIndex(friends);
            
            if(!~followers.indexOf(target)) {
              pruned = true;
              self.twit.post('friendships/destroy', { id: target }, callback);   
            }
          }
      });
  });
};

//
// search follow
//
Bot.prototype.searchFollow = function (params, callback) {
  var self = this;
 
  self.twit.get('search/tweets', params, function (err, reply) {
    if(err) return callback(err);
 
    var tweets = reply.statuses;
    var target = randIndex(tweets).user.id_str;
 
    self.twit.post('friendships/create', { id: target }, callback);
  });
};

//
// retweet
//
Bot.prototype.retweet = function (params, callback) {
  var self = this;
 
  self.twit.get('search/tweets', params, function (err, reply) {
    if(err) return callback(err);
 
    var tweets = reply.statuses;
    var randomTweet = randIndex(tweets);
 
    self.twit.post('statuses/retweet/:id', { id: randomTweet.id_str }, callback);
  });
};
 
//
// favorite a tweet
//
Bot.prototype.favorite = function (params, callback) {
  var self = this;
 
  self.twit.get('search/tweets', params, function (err, reply) {
    if(err) return callback(err);
 
    var tweets = reply.statuses;
    var randomTweet = randIndex(tweets);
 
    self.twit.post('favorites/create', { id: randomTweet.id_str }, callback);
  });
};

function randIndex (arr) {
  var index = Math.floor(arr.length*Math.random());
  return arr[index];
};

rtd2.js

//
// RTD2 - Twitter bot that tweets about the most popular github.com news
// Also makes new friends and prunes its followings.
//
var Bot = require("./bot")
, config1 = require("../config1");
 
var bot = new Bot(config1);
 
console.log('RTD2: Running.');
 
//get date string for today's date (e.g. 2011-01-01)
function datestring () {
  var d = new Date(Date.now() - 5*60*60*1000); //est timezone
  return d.getUTCFullYear() + "-" + 
         (d.getUTCMonth() + 1) + "-" + 
         d.getDate();
};
 
setInterval(function() {
  bot.twit.get("followers/ids", function(err, reply) {
    if(err) return handleError(err)
    console.log("\n# followers:" + reply.ids.length.toString());
  });
  var rand = Math.random();
  
  if(rand <= .10) {  // do a targeted follow
    var params = {
        q: "nodejs"
      , since: datestring()
      , result_type: "mixed"
    };
 
    bot.searchFollow(params, function(err, reply) {
      if(err) return handleError(err);
 
      var name = reply.screen_name;
      console.log("\nSearchFollow: followed @" + name);
    });
  } else if(rand <= .90) {  // retweet
    var params = {
        q: "nodejs"
      , since: datestring()
      , result_type: "mixed"
    };
 
    bot.retweet(params, function(err, reply) {
      if(err) return handleError(err);
 
      console.log("\nRetweet: retweeted response: " + reply.id);
    });
  } else if(rand <= .95) {  // favorite
    var params = {
        q: "nodejs"
      , since: datestring()
      , result_type: "mixed"
    };
 
    bot.favorite(params, function(err, reply) {
      if(err) return handleError(err);
 
      console.log("\nFavorite: favorited response: " + reply.id);
    });
  } else {                  //  prune a friend
    bot.prune(function(err, reply) {
      if(err) return handleError(err);
 
      var name = reply.screen_name
      console.log("\nPrune: unfollowed @"+ name);
    });
  }
}, 12000);
 
function handleError(err) {
  console.error("response status:", err.statusCode);
  console.error("data:", err.data);
}