trackers.js

'use strict';


// More detailed string pattern suffixes, stored by their common root.
const TRACKERS_BY_ROOT = {

  // Google's Urchin Tracking Module
  'utm_': [
    'source',
    'medium',
    'term',
    'campaign',
    'content',
    'name',
    'cid',
    'reader',
    'viz_id',
    'pubreferrer',
    'swu'
  ],

  // Adobe Omniture SiteCatalyst
  'IC': [
    'ID'
  ],

  // Adobe Omniture SiteCatalyst
  'ic': [
    'id'
  ],

  // Hubspot
  '_hs': [
    'enc',
    'mi'
  ],

  // Marketo
  'mkt_': [
    'tok'
  ],

  // MailChimp
  // https://developer.mailchimp.com/documentation/mailchimp/guides/getting-started-with-ecommerce/
  'mc_': [
    'cid',
    'eid'
  ],

  // comScore Digital Analytix?
  // http://www.about-digitalanalytics.com/comscore-digital-analytix-url-campaign-generator
  'ns_': [
    'source',
    'mchannel',
    'campaign',
    'linkname',
    'fee'
  ],

  // Simple Reach
  'sr_': [
    'share'
  ],

  // Vero
  'vero_': [
    'conv',
    'id'
  ],

  // Non-prefixy and 1-offs
  '': [
    // Facebook Click Identifier
    // http://thisinterestsme.com/facebook-fbclid-parameter/
    'fbclid',
    // Instagram Share Identifier
    'igshid',
    'srcid',
    // Google Click Identifier
    'gclid',
    // Some other Google Click thing
    'ocid',
    // Unknown
    'ncid',
    // Unknown
    'nr_email_referer',
    // Generic-ish. Facebook, Product Hunt and others
    'ref',
    // Alibaba-family 'super position model' tracker:
    // https://github.com/newhouse/url-tracking-stripper/issues/38
    'spm'
  ]
};

const ALL_TRACKERS = Object.keys(TRACKERS_BY_ROOT).reduce((trackers, root) => {
  TRACKERS_BY_ROOT[root].forEach(suffix => trackers.push(root + suffix));
  return trackers;
}, []);

const TRACKER_REGEXES_BY_TRACKER = ALL_TRACKERS.reduce((memo, tracker) => {
  memo[tracker] = new RegExp("((^|&)" + tracker + "=[^&#]*)", "ig");
  return memo;
}, {});

// Actually strip out the tracking codes/parameters from a URL and return the cleansed URL
function removeTrackersFromUrl(url, trackers) {
  if (!url) return url;

  const urlPieces = url.split('?');

  // If no params, nothing to modify
  if (urlPieces.length === 1) {
    return url;
  }

  trackers.forEach(tracker => {
    urlPieces[1] = urlPieces[1].replace(TRACKER_REGEXES_BY_TRACKER[tracker], '');
  });

  // If we've collapsed the URL to the point where there's an '&' against the '?'
  // then we need to get rid of that.
  while (urlPieces[1].charAt(0) === '&') {
    urlPieces[1] = urlPieces[1].substr(1);
  }

  return urlPieces[1] ? urlPieces.join('?') : urlPieces[0];
}




module.exports = {
  ALL_TRACKERS,
  removeTrackersFromUrl,
};