Using JavaScript generate a 32 character hexadecimal universal id string.

README.md

generateUnid

Each call returns a random 32 character hexidecimal string. Based on the work done https://gist.github.com/jed/982883

Usage:

<script src="https://gist.github.com/kevinbull/f1cbc5440aa713bd5c9e.js"></script>

var unid = generateUnid();
console.log(unid);

This was tested and created 300k unids in about 1 second with no duplicates on a 2018 MacBook Pro.

A stress test for creating a million unids is included in the code pen. Each time it was tested it never created duplicate unids.

Example: https://codepen.io/kbullman/pen/KKpjVJG?editors=1111

function uniqueArray(a) {
  //for a case insensitive version if array values are strings
  //return Array.from(new Set(a.map(v => v.toLowerCase())));
  // This is case sensitive
  return Array.from(new Set(a));
}

function generateUnids() {
  let unids = []
  let start = performance.now()
  for (let i = 0 ; i < 1000000 ; i++) {
    unids.push(generateUnid())
  }
  let elapsed = Number(performance.now() - start).toLocaleString()
  let uniqueItems = uniqueArray(unids)
  //let test = uniqueArray(['kevin', 'pepsi', 'Kevin', 'pepsi', 'Coke'])
  
  let msg = [
    `Elasped time ${elapsed} milliseconds`,
    `There were ${Number(unids.length - uniqueItems.length).toLocaleString()} duplicates out of ${unids.length.toLocaleString()} generated unids.`
    ]
  
  // The codepen has this element so it can be used in that context
  //document.getElementById("value").innerHTML = msg.join('<br />');
  console.log(msg)
}

generateUnid.js

function generateUnid(
  a                  // placeholder
){
  return a           // if the placeholder was passed, return
    ? (              // a random number from 0 to 15
      a ^            // unless b is 8,
      Math.random()  // in which case
      * 16           // a random number from
      >> a/4         // 8 to 11
      ).toString(16) // in hexadecimal
    : (              // or otherwise a concatenated string:
      [1e10] + 
      1e10 +
      1e9
      ).replace(     // replacing
        /[01]/g,     // zeroes and ones with
        generateUnid // random hex digits
      ).toUpperCase()
}