count.js

// GoatCounter: https://www.goatcounter.com
(function() {
  'use strict';

  if (window.goatcounter && window.goatcounter.vars)  // Compatibility
    window.goatcounter = window.goatcounter.vars
  else
    window.goatcounter = window.goatcounter || {}

  // Get all data we're going to send off to the counter endpoint.
  var get_data = function(vars) {
    var data = {
      p: (vars.path     === undefined ? goatcounter.path     : vars.path),
      r: (vars.referrer === undefined ? goatcounter.referrer : vars.referrer),
      t: (vars.title    === undefined ? goatcounter.title    : vars.title),
      e: !!(vars.event || goatcounter.event),
      s: [window.screen.width, window.screen.height, (window.devicePixelRatio || 1)],
      b: is_bot(),
      q: location.search,
    }

    var rcb, pcb, tcb  // Save callbacks to apply later.
    if (typeof(data.r) === 'function') rcb = data.r
    if (typeof(data.t) === 'function') tcb = data.t
    if (typeof(data.p) === 'function') pcb = data.p

    if (is_empty(data.r)) data.r = document.referrer
    if (is_empty(data.t)) data.t = document.title
    if (is_empty(data.p)) {
      var loc = location,
        c = document.querySelector('link[rel="canonical"][href]')
      if (c) {  // May be relative.
        loc = document.createElement('a')
        loc.href = c.href
      }
      data.p = (loc.pathname + loc.search) || '/'
    }

    if (rcb) data.r = rcb(data.r)
    if (tcb) data.t = tcb(data.t)
    if (pcb) data.p = pcb(data.p)
    return data
  }

  // Check if a value is "empty" for the purpose of get_data().
  var is_empty = function(v) { return v === null || v === undefined || typeof(v) === 'function' }

  // See if this looks like a bot; there is some additional filtering on the
  // backend, but these properties can't be fetched from there.
  var is_bot = function() {
    // Headless browsers are probably a bot.
    var w = window, d = document
    if (w.callPhantom || w._phantom || w.phantom)
      return 150
    if (w.__nightmare)
      return 151
    if (d.__selenium_unwrapped || d.__webdriver_evaluate || d.__driver_evaluate)
      return 152
    if (navigator.webdriver)
      return 153
    return 0
  }

  // Object to urlencoded string, starting with a ?.
  var urlencode = function(obj) {
    var p = []
    for (var k in obj)
      if (obj[k] !== '' && obj[k] !== null && obj[k] !== undefined && obj[k] !== false)
        p.push(encodeURIComponent(k) + '=' + encodeURIComponent(obj[k]))
    return '?' + p.join('&')
  }

  // Get the endpoint to send requests to.
  var get_endpoint = function() {
    var s = document.querySelector('script[data-goatcounter]');
    if (s && s.dataset.goatcounter)
      return s.dataset.goatcounter
    return (goatcounter.endpoint || window.counter)  // counter is for compat; don't use.
  }

  // Filter some requests that we (probably) don't want to count.
  goatcounter.filter = function() {
    if ('visibilityState' in document && (document.visibilityState === 'prerender' || document.visibilityState === 'hidden'))
      return 'visibilityState'
    if (!goatcounter.allow_frame && location !== parent.location)
      return 'frame'
    if (!goatcounter.allow_local && location.hostname.match(/(localhost$|^127\.|^10\.|^172\.(1[6-9]|2[0-9]|3[0-1])\.|^192\.168\.)/))
      return 'local'
    if (localStorage.getItem('skipgc') === 't')
      return 'disabled with #toggle-goatcounter'
    return false
  }

  // Get URL to send to GoatCounter.
  window.goatcounter.url = function(vars) {
    var data = get_data(vars || {})

    // Changed to strip ?ref=campaign from the url if it's the only query parameter
    if (data.q && /\?ref=[^&]*$/.test(data.q))
      history.replaceState(undefined, undefined, data.p.replace(data.q, ''))

    if (data.p === null)  // null from user callback.
      return
    data.rnd = Math.random().toString(36).substr(2, 5)  // Browsers don't always listen to Cache-Control.

    var endpoint = get_endpoint()
    if (!endpoint) {
      if (console && 'warn' in console)
        console.warn('goatcounter: no endpoint found')
      return
    }

    return endpoint + urlencode(data)
  }

  // Count a hit.
  window.goatcounter.count = function(vars) {
    var f = goatcounter.filter()
    if (f) {
      if (console && 'log' in console)
        console.warn('goatcounter: not counting because of: ' + f)
      return
    }

    var url = goatcounter.url(vars)
    if (!url) {
      if (console && 'log' in console)
        console.warn('goatcounter: not counting because path callback returned null')
      return
    }

    var img = document.createElement('img')
    img.src = url
    img.style.position = 'absolute'  // Changed to prevent page reflow
    img.setAttribute('alt', '')
    img.setAttribute('aria-hidden', 'true')

    var rm = function() { if (img && img.parentNode) img.parentNode.removeChild(img) }
    setTimeout(rm, 3000)  // In case the onload isn't triggered.
    img.addEventListener('load', rm, false)
    document.body.appendChild(img)
  }

  // Get a query parameter.
  window.goatcounter.get_query = function(name) {
    var s = location.search.substr(1).split('&')
    for (var i = 0; i < s.length; i++)
      if (s[i].toLowerCase().indexOf(name.toLowerCase() + '=') === 0)
        return s[i].substr(name.length + 1)
  }

  // Track click events.
  window.goatcounter.bind_events = function() {
    if (!document.querySelectorAll)  // Just in case someone uses an ancient browser.
      return

    var send = function(elem) {
      return function() {
        goatcounter.count({
          event:    true,
          path:     (elem.dataset.goatcounterClick || elem.name || elem.id || ''),
          title:    (elem.dataset.goatcounterTitle || elem.title || (elem.innerHTML || '').substr(0, 200) || ''),
          referrer: (elem.dataset.goatcounterReferrer || elem.dataset.goatcounterReferral || ''),
        })
      }
    }

    Array.prototype.slice.call(document.querySelectorAll("*[data-goatcounter-click]")).forEach(function(elem) {
      if (elem.dataset.goatcounterBound)
        return
      var f = send(elem)
      elem.addEventListener('click', f, false)
      elem.addEventListener('auxclick', f, false)  // Middle click.
      elem.dataset.goatcounterBound = 'true'
    })
  }

  // Make it easy to skip your own views.
  if (location.hash === '#toggle-goatcounter')
    if (localStorage.getItem('skipgc') === 't') {
      localStorage.removeItem('skipgc', 't')
      alert('GoatCounter tracking is now ENABLED in this browser.')
    }
  else {
    localStorage.setItem('skipgc', 't')
    alert('GoatCounter tracking is now DISABLED in this browser until ' + location + ' is loaded again.')
  }

  if (!goatcounter.no_onload) {
    var go = function() {
      goatcounter.count()
      if (!goatcounter.no_events)
        goatcounter.bind_events()
    }

    if (document.body === null)
      document.addEventListener('DOMContentLoaded', function() { go() }, false)
    else
      go()
  }
})();