postal.js/example/node/collectors/mentioner-count.js

var _ = require('underscore'),
	_scanner = function(regExp, text, callback) {
	var match;
		while(text.search(regExp) !== -1) {
			match = regExp.exec(text);
			if(match && match[1]) {
				callback(match[1].toLowerCase());
			}
			text = text.replace(regExp, "");
		}
	},
	MentionerCount = function(namespace) {
		this.namespace = namespace;

		this.events = {};

	    this.mentioners = { list: [], registry: {} };

	    this.lastStats = undefined;
	};

MentionerCount.prototype = {
	init: function() {
		this.mentioners = { list: [], registry: {} };
		this.lastStats = undefined;
	},
	on: function( eventName, callback ) {
		if( !this.events[ eventName ] ) {
			this.events[ eventName ] = [];
		}
		this.events[ eventName ].push( callback );
		return function() {
			this.events[ eventName ] = _.without( this.events[ eventName ], callback );
		}.bind( this );
	},
	raiseEvent: function( eventName, data ) {
		if( this.events[ eventName ] ) {
			this.events[ eventName ].forEach( function( callback ){
				callback( data );
			});
		}
	},
	processNewTweets: function(tweets) {
		tweets.forEach(function(tweet){
			this.processMentioners(tweet);
		}, this);
		this.lastStats = { type: "MentionerCount", mentioners: this.mentioners.list };
		this.raiseEvent( this.namespace, this.lastStats );
	},
	processMentioners: function(tweet) {
		_scanner(/@(\w*)/i, tweet.text, function(mentioned) {
			if(!this.mentioners.registry[tweet.from_user]) {
				var obj = { user: tweet.from_user, count: 0, image: tweet.profile_image_url };
				this.mentioners.registry[tweet.from_user] = obj;
				this.mentioners.list.push(obj);
			}
			this.mentioners.registry[tweet.from_user].count++;
		}.bind(this));
	}
};

module.exports = MentionerCount;