hexo/node_modules/cuid/lib/fingerprint.browser.js

var pad = require('./pad.js');

var env = typeof window === 'object' ? window : self;
var globalCount = Object.keys(env).length;
var mimeTypesLength = navigator.mimeTypes ? navigator.mimeTypes.length : 0;
var clientId = pad((mimeTypesLength +
  navigator.userAgent.length).toString(36) +
  globalCount.toString(36), 4);

module.exports = function fingerprint () {
  return clientId;
};