Simple chatbot using multimethod.js

bot.js

var multimethod = require('multimethod');
var _ = require('underscore');

// expected message format: {from: String, text: String}

var Bot = function() {
  this.regexps = {};
  this.dispatcher = multimethod().dispatch(function(message) {

    var regexp = _.find(this.regexps, function(regexp, key) {
      return regexp.test(message.text);
    });

    if (regexp) return regexp.toString();
  });
};

Bot.prototype.listen = function(message) {
  return this.dispatcher(message);
};

Bot.prototype.respond = function(condition, fn) {
  var key = condition.toString();
  this.regexps[key] = condition;
  this.dispatcher.when(key, fn);
}

var myBot = new Bot();

myBot.respond(/hello/i, function(message) {
  console.log( "Hello to you too "+ message.from +" :)" );
});

myBot.respond(/now\?/, function(message) {
  console.log( message.from +", current time is: "+ new Date().toString() );
});

myBot.listen( {from: "Adam", text: "Hello man, how are you?"} );
myBot.listen( {from: "Boris", text: "now?"} );
myBot.listen( {from: "Cedric", text: "This should not match anything..."} );