bestchoice/app/index.js

Self Learning Weighted Multivariate Testing Module

'use strict';

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

var EpsilonGreedy = require('./lib/epsilon-greedy.js');
var UCB1 = require('./lib/ucb1.js');

var campaigns = [];

var Campaign = function () {
  function Campaign(campaignID, targetURL, variants, epsilon, frequency) {
    _classCallCheck(this, Campaign);

    this.campaignID = campaignID;
    this.targetURL = targetURL;
    this.variants = variants;
    this.stats = [];
    this.visitsQueue = [];
    this.epsilon = epsilon;
    this.frequency = frequency;
  }

  _createClass(Campaign, [{
    key: 'init',
    value: function init() {
      var counts = arguments.length <= 0 || arguments[0] === undefined ? 0 : arguments[0];
      var values = arguments.length <= 1 || arguments[1] === undefined ? 0 : arguments[1];

      var len = this.variants.length;
      var counts = new Array(len).fill(0);
      var values = new Array(len).fill(0);
      this.stats = new EpsilonGreedy(this.epsilon, counts, values);
      return true;
    }
  }]);

  return Campaign;
}();

;

// Get running campaign
var getCampaignByID = function getCampaignByID(campaignID) {

  var findId = function findId(campaign) {
    return campaign.campaignID === campaignID;
  };
  return campaigns.find(findId);
};

// Find a page by cookie name
var findCookie = function findCookie(cookie) {
  var campaign = getCampaignByID(campaignID);
  var cookiePosition = campaign.visitsQueue.map(function (e) {
    return e.cookie;
  }).indexOf(cookie);
};

// Get unconverted visit
var getVisit = function getVisit(campaignID, cookie, variant) {
  var campaign = getCampaignByID(campaignID);
  var variantID = campaign.variants.indexOf(variant);
  var cookie = cookie;
  var findCookie = function findCookie(visit) {
    return visit.cookie === cookie;
  };

  return campaign.variants[campaign.stats.selectArm()];
};

// Register variant visit
var addToVisitQueue = function addToVisitQueue(campaignID, targetURL, cookie) {
  var time = new Date().getTime();
  var campaignID = getCampaignByID(campaignID);
  var variant = campaignID.variants.indexOf(targetURL);

  campaignID.visitsQueue.push({
    time: time,
    cookie: cookie,
    variant: variant
  });
  return cookie;
};

var updateExpiredVisits = function updateExpiredVisits(campaignID) {
  var timeNow = new Date().getTime();
  var campaign = getCampaignByID(campaignID);
  var campaignIndex = campaigns.map(function (e) {
    return e.campaignID;
  }).indexOf(campaignID);
  var queue = campaigns[campaignIndex].visitsQueue;

  //check every item in campaigns visits queue and remove the expired ones while adjusting the weights
  queue.filter(function (e) {
    var minutesPassed = Math.round((timeNow - e.time) / 1000 / 60);

    // check if
    if (minutesPassed > campaign.frequency) {
      var expiredItem = campaigns[campaignIndex].visitsQueue.splice(queue.indexOf(e), 1);
      //console.log(campaignIndex + " is the index");

      var variant = e.variant;
      //console.log(e.variant + "variant to delete");

      var reward = 0;
      campaigns[campaignIndex].stats.update(variant, reward);

      console.log('removed expired');
      return true;
    } else {
      return false;
    }
  });

  //campaigns[campaignIndex].visitsQueue = cleanList.slice(0);
};

module.exports = {

  // Add page to the Campaign
  addCampaign: function addCampaign(campaignID, targetURL, variants, epsilon, frequency) {
    var _campaignID = campaignID;
    campaigns.push(campaignID = new Campaign(campaignID, targetURL, variants, epsilon, frequency));
    getCampaignByID(_campaignID).init();
    return true;
  },

  // Remove page from the Campaign
  removeCampaign: function removeCampaign(campaignID) {
    return campaigns.splice(campaigns.indexOf(getCampaignByID(campaignID)), 1);
  },

  // Return all availible campaigns
  getCampaigns: function getCampaigns() {
    return campaigns;
  },

  // Return all availible campaigns as JSON
  saveCampaigns: function saveCampaigns() {
    return JSON.stringify(campaigns);
  },

  // Load campaigns from JSON file
  loadCampaigns: function loadCampaigns(data) {
    campaigns = JSON.parse(data);
    return true;
  },

  // Register visit
  getPage: function getPage(campaignID, targetURL) {
    var cookie = arguments.length <= 2 || arguments[2] === undefined ? 0 : arguments[2];


    var campaign = getCampaignByID(campaignID); // get current campaign object

    // if cookie is not set
    if (cookie === 0) {

      // select the page by using the decision algorythm from availible variants
      //console.log(campaign.stats.selectArm() + "is variant to show");

      var variantToShow = campaign.variants[campaign.stats.selectArm()];

      // create a random string
      var cookie = Math.random().toString(36).slice(2);

      // add to the unconverted visits queue
      addToVisitQueue(campaignID, variantToShow, cookie);

      return {

        // variant URL to show
        pageVariant: getVisit(campaignID, cookie, variantToShow),
        // newly generated cookie
        cookie: cookie,
        // campaign ID
        campaignID: campaignID
      };
    }

    // if cookie already exists return the existing information

    else {

        // TODO reset cookie time in the visit queue

        return {
          pageVariant: getVisit(campaignID, cookie, targetURL),
          cookie: cookie,
          campaignID: campaignID
        };
      }
  },

  // Register variant conversion
  registerConversion: function registerConversion(campaignID, targetURL, cookie) {
    var reward = arguments.length <= 3 || arguments[3] === undefined ? 1 : arguments[3];


    var campaign = getCampaignByID(campaignID);
    var variantID = campaign.variants.indexOf(targetURL);
    var findCookie = function findCookie(visit) {
      return visit.cookie === cookie;
    };

    var cookiePosition = campaign.visitsQueue.map(function (e) {
      return e.cookie;
    }).indexOf(cookie);
    if (cookiePosition === -1) {
      return;
    }
    var variant = campaign.variants.indexOf(targetURL);
    campaign.stats.update(variant, reward);

    campaign.visitsQueue.splice(cookiePosition, 1);
    return true;
  },

  updateExpiredVisits: updateExpiredVisits

};