botty.js

var botty = (function() {
  'use strict';

  var d = {
    // Record client timestamp
    ct: new Date().getTime(),
    ctD: 0,
    // Record obvious red flags
    rf: (
      window.callPhantom === undefined
      && window._phantom === undefined
      && window.phantom === undefined
      && window.__nightmare === undefined
      && (navigator.webdriver === undefined || navigator.webdriver === false)
      && document.__selenium_unwrapped === undefined
      && document.__webdriver_evaluate === undefined
      && document.__driver_evaluate === undefined
    ),
    // Mouse movement data points
    mmX: 0,
    mmY: 0,
    mmD: 0,
    // Mouse click data point
    mcC: 0,
    // Scroll data points
    sY: 0,
    sD: 0,
    // Keypress data points
    kpC: 0,
    kpT: new Date().getTime(),
    kpTl: [],
    kpTA: 0,
  };
  // Record mouse movement travelled
  window.addEventListener('mousemove', (event) => {
    d.mmD = Math.abs(d.mmX - event.clientX) + Math.abs(d.mmY - event.clientY);
    d.mmX = event.clientX;
    d.mmY = event.clientY;
  });
  // Record mouse clicks
  window.addEventListener('click', (event) => {
    d.mcC += 1;
  });
  // Record scroll position travelled
  window.addEventListener('scroll', (event) => {
    d.sD = Math.abs(d.sY - window.scrollY);
    d.sY = window.scrollY;
  });
  // Record key press count and average time (ms) between key presses (last 100)
  window.addEventListener('keydown', (event) => {
    d.kpC += 1;
    var kpT = new Date().getTime();
    d.kpTl.push(kpT - d.kpT);
    d.kpT = kpT;
    if (d.kpTl.length > 100) {
      d.kpTl.shift();
    }
    var sum = 0;
    for (var i = 0; i<d.kpTl.length; i++) {
      sum += d.kpTl[i];
    }
    d.kpTA = sum / d.kpT.length;
  });


  return function() {
    d.ctD = new Date().getTime() - d.ct;
    return btoa(JSON.stringify(d));
  }
})();