this list is now archived - look inside https://github.com/sw-yx/brain if you would like an updated list! thank you.

uuid-list

list of unique id implementations, design considerations, and resources. may also overlap somewhat with the topic of hashing

Desirable Properties

• extremely low chance of collision
• sorting
  • chronologically sortable
  • lexicographically/alphabetically sortable? (k-sortable?)
• speed
  • completely random hurts perf
• string qualities
  • case insensitive
  • URL safe
  • 64 bits (instead of 128bits) or otherwise fixed length (bc of storage concerns)
• secure/good entropy
  • non-secure = Math.random + Date.now
  • cryptographically secure = CSPRNG - use crypto module in node.js
  • ?
• inputs:
  • timestamp
  • string?
• no dependencies
• no need for coordination (among different clients generating uuid's)

Concepts

• https://en.wikipedia.org/wiki/Universally_unique_identifier

• RFC: A Universally Unique IDentifier (UUID) URN Namespace - https://tools.ietf.org/html/rfc4122

• k-sorting http://ci.nii.ac.jp/naid/110002673489/

  We’re aiming to keep our k below 1 second, meaning that tweets posted within a second of one another will be within a second of one another in the id space too.

• KSUID's https://github.com/segmentio/ksuid (segment)

• FUUID https://github.com/kpdemetriou/fuuid UUIDs are compatible with regular UUIDs but are naturally ordered by generation time, collision-free and support succinct representations such as raw binary and base58-encoded strings.

  • Warning - not mature https://news.ycombinator.com/item?id=27030088

• ulid's https://github.com/ulid/spec (instagram, firebase)

• c4 ID's http://www.cccc.io/

• MongoDB ObjectID: https://www.mongodb.com/blog/post/generating-globally-unique-identifiers-for-use-with-mongodb

• guid alternatives https://www.softwareatscale.dev/p/guids-are-not-enough

• UUID and MySQL performance - YouTube discussion

  • MySQL is clustered by default on the primary key which means inserts have to be ordered, so UUID (random in nature) has bad performance in MySQL.

Impls

grab n go: https://www.uuidgenerator.net/

super simple dumb unique id

function id () {
  return Math.random().toString(36).substring(2) + Date.now().toString(36);
}

better uuid?

https://www.w3resource.com/javascript-exercises/javascript-math-exercise-23.php
export function uuid() {
  var dt = new Date().getTime()
  var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(
    c
  ) {
    var r = (dt + Math.random() * 16) % 16 | 0
    dt = Math.floor(dt / 16)
    // eslint-disable-next-line
    return (c == 'x' ? r : (r & 0x3) | 0x8).toString(16)
  })
  return uuid
}

• Twitter Snowflake (2010-2014) https://blog.twitter.com/engineering/en_us/a/2010/announcing-snowflake.html

• ULID https://github.com/ulid/spec (security concern)

• Timeflake https://github.com/anthonynsimon/timeflake (not for security)

• fast random ID:

  • https://github.com/lukeed/uid A tiny (134B) and fast utility to generate random IDs of fixed length

    import { uid } from 'uid';
    // or: import { uid } from 'uid/secure';
    // or: import { uid } from 'uid/single';
    
    // length = 11 (default)
    uid(); //=> 'fsm2vsgo1pr'
    uid(); //=> 'gf34sezvoh6'
    
    // customize length
    uid(16); //=> 'zbb6cc3ay26omrdz'
    uid(25); //=> 'lljjmo3f39rnjudsgqvzta1rb'
    uid(32); //=> 'yrfiw88qlq1fgpm40lguz6u43gksfj4a'

  • https://github.com/lukeed/hexoid like (uid but >3x faster due to different api)

  • https://github.com/ericelliott/cuid Collision-resistant ids optimized for horizontal scaling and binary search lookup performance.

  • https://github.com/ai/nanoid A tiny (108 bytes), secure, URL-friendly, unique string ID generator for JavaScript. Comparison vs uuid

    import { nanoid } from 'nanoid'
    model.id = nanoid() //=> "V1StGXR8_Z5jdHi6B-myT"

• uuid/v4:

  • as of Node v14.17 you can generate UUID4's with the crypto module:

    const { randomUUID } = require('crypto');
    console.log(randomUUID());
    // 'aa7c91a1-f8fc-4339-b9db-f93fc7233429'

  • https://digitalbunker.dev/2020/09/30/understanding-how-uuids-are-generated/
  • https://github.com/lukeed/uuid
  • https://github.com/uuidjs/uuid

  import { v4 as uuidv4 } from 'uuid';
  uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'