Unique Nonce Generator

nonce.js

const {
  randomFill
} = require('crypto')

const dirtyNonce = {}

const _nonce = () => {
  const buf = Buffer.alloc(16)
  return new Promise((resolve, reject) => {
    randomFill(buf, (err, buf) => {
      if (err) { reject(err) }
      console.log(buf.toString('hex'))
      resolve(buf)
    })
  })
}

const nonceGenerator = async () => {
  console.time(`nonce generator`)
  let nonce = await _nonce()
  while (isDirty(nonce)) {
    nonce = await _nonce()
  }
  console.timeEnd(`nonce generator`)
  return nonce
}

const isDirty = nonce => {
  const iv = nonce.toString('hex')
  if (dirtyNonce[iv]) {
    return true
  }
  dirtyNonce[iv] = true
  return false
}

const isClean = nonce => !(isDirty(nonce))

const dirty = () => (
  Object.keys(dirtyNonce)
)