Short Unique ID (UUID) Generating Library

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Tiny (6.7kB minified) no-dependency library for generating random or sequential UUID of any length with exceptionally minuscule probabilies of duplicate IDs.

1const uid = new ShortUniqueId({ length: 10 });
2uid.rnd(); // p0ZoB1FwH6
3uid.rnd(); // mSjGCTfn8w
4uid.rnd(); // yt4Xx5nHMB
5// ...
6
7// or
8
9const { randomUUID } = new ShortUniqueId({ length: 10 });
10randomUUID(); // e8Civ0HoDy
11randomUUID(); // iPjiGoHXAK
12randomUUID(); // n528gSMwTN
13// ...

For example, using the default dictionary of numbers and letters (lower and upper case):

1  0,1,2,3,4,5,6,7,8,9,
2  a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,
3  A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z

• if you generate a unique ID of 16 characters (half of the standard UUID of 32 characters)
• generating 100 unique IDs per second

It would take ~10 thousand years to have a 1% probability of at least one collision!

To put this into perspective:

• 73 years is the (global) average life expectancy of a human being
• 120 years ago no human ever had set foot on either of the Earth's poles
• 480 years ago Nicolaus Copernicus was still working on his theory of the Earth revolving around the Sun
• 1000 years ago there was no such thing as government-issued paper money (and wouldn't be for about a century)
• 5000 years ago the global population of humans was under 50 million (right now Mexico has a population of 127 million)

You can calculate duplicate/collision probabilities using the included functions:

• availableUUIDs()
• approxMaxBeforeCollision()
• collisionProbability()

NOTE: 👆 On these links you will also find explanations for the math used within the functions.

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Open source notice

This project is part of the Open Collective project Simply Hexagonal and is open to updates by its users, we ensure that PRs are relevant to the community. In other words, if you find a bug or want a new feature, please help us by becoming one of the contributors ✌️ ! See the contributing section.

Like this module? ❤

Please consider:

• Buying me a coffee ☕
• Supporting me on Patreon 🏆
• Starring this repo on Github 🌟

📣 v5 Notice

In order to improve security compliance we have removed the ability to use a ShortUniqueId as a function, i.e. const uid = new ShortUniqueId(); uid(); is no longer supported.

If you plan to upgrade to v5 make sure to refactor uid(); to uid.rnd(); in your code beforehand.

For more information regarding this decision you can view issue #53.

Features

Ability to generate UUIDs that contain a timestamp which can be extracted:

1// js/ts
2
3const uid = new ShortUniqueId();
4
5const uidWithTimestamp = uid.stamp(32);
6console.log(uidWithTimestamp);
7// GDa608f973aRCHLXQYPTbKDbjDeVsSb3
8
9const recoveredTimestamp = uid.parseStamp(uidWithTimestamp);
10console.log(recoveredTimestamp);
11// 2021-05-03T06:24:58.000Z

1# cli
2
3$ suid -s -l 42
4
5  lW611f30a2ky4276g3l8N7nBHI5AQ5rCiwYzU47HP2
6
7$ suid -p lW611f30a2ky4276g3l8N7nBHI5AQ5rCiwYzU47HP2
8
9  2021-08-20T04:33:38.000Z

Default dictionaries (generated on the spot to reduce memory footprint and avoid dictionary injection vulnerabilities):

• number
• alpha
• alpha_lower
• alpha_upper
• alphanum (default when no dictionary is provided to new ShortUniqueId())
• alphanum_lower
• alphanum_upper
• hex

1// instantiate using one of the default dictionary strings
2const uid = new ShortUniqueId({
3  dictionary: 'hex',
4});
5
6console.log(uid.dict.join());
7// 0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f
8
9// or change the dictionary after instantiation
10uid.setDictionary('alpha_upper');
11
12console.log(uid.dict.join());
13// A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z

Ability to use custom formatting

Where $r is random UUID, $s is sequential UUID, and $t is timestamp UUID:

1const timestamp = new Date('4-01-29T03:21:21.000Z');
2const result = uid.formattedUUID('Time: $t0 ID: $s2-$r4', timestamp); // timestamp is optional
3
4console.log(result);
5// Time: 63d5e631 ID: 0b-aaab

Ability to validate UUIDs against the instance dictionary or a provided dictionary

Example of using .validate() method:

1// Instantiate using one of the default dictionary strings
2const uid = new ShortUniqueId({
3  dictionary: 'hex',
4});
5
6const uuid = uid.stamp(32); // Generate a UUID
7
8// Validate the generated UUID against the instance dictionary
9const isValid = uid.validate(uuid);
10
11console.log(`Is the UUID valid? ${isValid}`);
12
13// ---
14
15// Validate the generated UUID against the provided dictionary
16const customDictionary = ['a', 'b', /* ... */];
17const isValid = uid.validate(uuid, customDictionary);
18
19console.log(`Is the UUID valid? ${isValid}`);

Use in CLI

1$ npm install --global short-unique-id
2
3$ suid -h
4
5# Usage:
6#   node short-unique-id [OPTION]
7# 
8# Options:
9#   -l, --length=ARG         character length of the uid to generate.
10#   -s, --stamp              include timestamp in uid (must be used with --length (-l) of 10 or more).
11#   -t, --timestamp=ARG      custom timestamp to parse (must be used along with -s, --stamp, -f, or --format).
12#   -f, --format=ARG         string representing custom format to generate id with.
13#   -p, --parse=ARG          extract timestamp from stamped uid (ARG).
14#   -d, --dictionaryJson=ARG json file with dictionary array.
15#   -h, --help               display this help

Use as module

Add to your project:

1// ES6 / TypeScript Import
2import ShortUniqueId from 'short-unique-id';
3
4// Node.js require
5const ShortUniqueId = require('short-unique-id');
6
7// Deno (web module) Import
8import ShortUniqueId from 'https://esm.sh/short-unique-id';

Instantiate and use:

1//Instantiate
2const uid = new ShortUniqueId();
3
4// Random UUID
5console.log(uid.rnd());
6
7// Sequential UUID
8console.log(uid.seq());

alternatively using destructuring assignment:

1// Instantiate and destructure (long method name recommended for code readability)
2const { randomUUID, sequentialUUID } = new ShortUniqueId();
3
4// Random UUID
5console.log(randomUUID());
6
7// Sequential UUID
8console.log(sequentialUUID());

NOTE: we made sure to use bind() on all ShortUniqueId methods to ensure that any options passed when creating the instance will be respected by the destructured methods.

Use in browser

1<!-- Add source (minified 4.6kB) -->
2<script src="https://cdn.jsdelivr.net/npm/short-unique-id@latest/dist/short-unique-id.min.js"></script>
3
4<!-- Usage -->
5<script>
6  // Instantiate
7  var uid = new ShortUniqueId();
8
9  // Random UUID
10  document.write(uid.rnd());
11
12  // Sequential UUID
13  document.write(uid.seq());
14</script>

Options

Options can be passed when instantiating uid:

1const options = { ... };
2
3const uid = new ShortUniqueId(options);

For more information take a look at the docs.

Available for

• Node.js (npm)
• Deno
• Browsers

Documentation with Online Short UUID Generator

You can find the docs and online generator at:

https://shortunique.id

What is the probability of generating the same id again?

This largely depends on the given dictionary and the selected UUID length.

Out of the box this library provides a shuffled dictionary of digits from 0 to 9, as well as the alphabet from a to z both in UPPER and lower case, with a default UUID length of 6. That gives you a total of 56,800,235,584 possible UUIDs.

So, given the previous values, the probability of generating a duplicate in 1,000,000 rounds is ~0.00000002, or about 1 in 50,000,000.

If you change the dictionary and/or the UUID length then we have provided the function collisionProbability() function to calculate the probability of hitting a duplicate in a given number of rounds (a collision) and the function uniqueness() which provides a score (from 0 to 1) to rate the "quality" of the combination of given dictionary and UUID length (the closer to 1, higher the uniqueness and thus better the quality).

To find out more about the math behind these functions please refer to the API Reference.

Acknowledgement and platform support

This repo and npm package started as a straight up manual transpilation to ES6 of the short-uid npm package by Ankit Kuwadekar.

Since this package is now reporting 200k+ npm weekly downloads and 16M+ weekly cdn hits, we've gone ahead and re-written the whole of it in TypeScript and made sure to package dist modules compatible with Deno, Node.js and all major Browsers.

Sponsors

• Clever Synapse

Development

Clone this repo:

1# SSH
2git clone git@github.com:jeanlescure/short-unique-id.git
3
4# HTTPS
5git clone https://github.com/jeanlescure/short-unique-id.git

Tests run using:

pnpm test

Build

In order to publish the latest changes you must build the distribution files:

pnpm build

Then commit all changes and run the release script:

pnpm release

Contributing

Yes, thank you! This plugin is community-driven, most of its features are from different authors. Please update the docs and tests and add your name to the package.json file.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

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💻 👀	💻	💻	🤔
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👀

License

Copyright (c) 2018-2025 Short Unique ID Contributors.
Licensed under the Apache License 2.0.