Generate UUID v4

uuid4.js

/**
 * Generates UUID identifier - version 4, variant DCE 1.1, ISO/IEC 11578:1996
 *
 * @returns {String} - UUID identifier
 *
 * https://en.wikipedia.org/wiki/Universally_unique_identifier
 * https://www.uuidtools.com/decode
 * https://www.uuidtools.com/generate/v4
 */
const uuid = () => {
  const rand = [...Array(32)].map(() => Math.floor(Math.random() * 16).toString(16)).join('');
  const variant = ['8', '9', 'a', 'b'];
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/x/g, (c, i) => (`${rand}${rand}`)[i])
    .replace('y', variant[Math.floor(Math.random() * variant.length)]);
};

// https://jsfiddle.net/7e3buj4L/
// 
// 7089366c-a2e5-4e8b-a5fb-1fc9a5567089
// 06119031-7e14-461b-8ed7-3125563d0611
// e8e784ee-8d13-4458-a385-c9992bc9e8e7