create a short alphanumeric hash using shake128

short-hash.js

const crypto = require('crypto')

// create hash of user sub, and append it to the first 8 characters of the user sub
function getHash (sub) {
  const hash = crypto
  .createHash('shake128', {outputLength: 6})
  .update(sub, 'utf-8')
  .digest('base64')
  // you could remove this replace statement if you didn't want to alter the base64 or number of output characters
  // this is here so that only alphanumerics are returned. but it does change the length of some hashes (consistently)
  .replace('+', '')
  return sub.split('@').shift().slice(0, 8) + hash
}

module.exports = getHash

oh, it's for Node.js of course