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uuid  

For the creation of RFC4122 UUIDs

• Complete - Support for RFC4122 version 1, 3, 4, and 5 UUIDs
• Cross-platform - Support for ...
  • CommonJS, [ECMAScript Modules](#ecmascript-modules) and [CDN builds](#cdn-builds)
  • Node 8, 10, 12, 14
  • Chrome, Safari, Firefox, Edge, IE 11 browsers
  • Webpack and rollup.js module bundlers
  • [React Native / Expo](#react-native--expo)
• Secure - Cryptographically-strong random values
• Small - Zero-dependency, small footprint, plays nice with "tree shaking" packagers
• CLI - Includes the [uuid command line](#command-line) utility

Upgrading from uuid@3.x? Your code is probably okay, but check out [Upgrading From uuid@3.x](#upgrading-from-uuid3x) for details.

Quickstart

To create a random UUID...

1. Install

shell
npm install uuid

2. Create a UUID (ES6 module syntax)

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

... or using CommonJS syntax:

javascript
const { v4: uuidv4 } = require('uuid');
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'

For timestamp UUIDs, namespace UUIDs, and other options read on ...

API Summary

API

uuid.NIL

The nil UUID string (all zeros).

Example:

javascript
import { NIL as NIL_UUID } from 'uuid';

NIL_UUID; // ⇨ '00000000-0000-0000-0000-000000000000'

uuid.parse(str)

Convert UUID string to array of bytes

Note: Ordering of values in the byte arrays used by parse() and stringify() follows the left &Rarr; right order of hex-pairs in UUID strings. As shown in the example below.

Example:

javascript
import { parse as uuidParse } from 'uuid';

// Parse a UUID
const bytes = uuidParse('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b');

// Convert to hex strings to show byte order (for documentation purposes)
[...bytes].map((v) => v.toString(16).padStart(2, '0')); // ⇨ 
  // [
  //   '6e', 'c0', 'bd', '7f',
  //   '11', 'c0', '43', 'da',
  //   '97', '5e', '2a', '8a',
  //   'd9', 'eb', 'ae', '0b'
  // ]

uuid.stringify(arr[, offset])

Convert array of bytes to UUID string

Note: Ordering of values in the byte arrays used by parse() and stringify() follows the left &Rarr; right order of hex-pairs in UUID strings. As shown in the example below.

Example:

javascript
import { stringify as uuidStringify } from 'uuid';

const uuidBytes = [
  0x6e,
  0xc0,
  0xbd,
  0x7f,
  0x11,
  0xc0,
  0x43,
  0xda,
  0x97,
  0x5e,
  0x2a,
  0x8a,
  0xd9,
  0xeb,
  0xae,
  0x0b,
];

uuidStringify(uuidBytes); // ⇨ '6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'

uuid.v1([options[, buffer[, offset]]])

Create an RFC version 1 (timestamp) UUID

Note: The default node id (the last 12 digits in the UUID) is generated once, randomly, on process startup, and then remains unchanged for the duration of the process.

Note: options.random and options.rng are only meaningful on the very first call to v1(), where they may be passed to initialize the internal node and clockseq fields.

Example:

javascript
import { v1 as uuidv1 } from 'uuid';

uuidv1(); // ⇨ '2c5ea4c0-4067-11e9-8bad-9b1deb4d3b7d'

Example using options:

javascript
import { v1 as uuidv1 } from 'uuid';

const v1options = {
  node: [0x01, 0x23, 0x45, 0x67, 0x89, 0xab],
  clockseq: 0x1234,
  msecs: new Date('2011-11-01').getTime(),
  nsecs: 5678,
};
uuidv1(v1options); // ⇨ '710b962e-041c-11e1-9234-0123456789ab'

uuid.v3(name, namespace[, buffer[, offset]])

Create an RFC version 3 (namespace w/ MD5) UUID

API is identical to v5(), but uses "v3" instead.

&#x26a0;&#xfe0f; Note: Per the RFC, "_If backward compatibility is not an issue, SHA-1 [Version 5] is preferred_."

uuid.v4([options[, buffer[, offset]]])

Create an RFC version 4 (random) UUID

Example:

javascript
import { v4 as uuidv4 } from 'uuid';

uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'

Example using predefined random values:

javascript
import { v4 as uuidv4 } from 'uuid';

const v4options = {
  random: [
    0x10,
    0x91,
    0x56,
    0xbe,
    0xc4,
    0xfb,
    0xc1,
    0xea,
    0x71,
    0xb4,
    0xef,
    0xe1,
    0x67,
    0x1c,
    0x58,
    0x36,
  ],
};
uuidv4(v4options); // ⇨ '109156be-c4fb-41ea-b1b4-efe1671c5836'

uuid.v5(name, namespace[, buffer[, offset]])

Create an RFC version 5 (namespace w/ SHA-1) UUID

Note: The RFC DNS and URL namespaces are available as v5.DNS and v5.URL.

Example with custom namespace:

javascript
import { v5 as uuidv5 } from 'uuid';

// Define a custom namespace.  Readers, create your own using something like
// https://www.uuidgenerator.net/
const MY_NAMESPACE = '1b671a64-40d5-491e-99b0-da01ff1f3341';

uuidv5('Hello, World!', MY_NAMESPACE); // ⇨ '630eb68f-e0fa-5ecc-887a-7c7a62614681'

Example with RFC URL namespace:

javascript
import { v5 as uuidv5 } from 'uuid';

uuidv5('https://www.w3.org/', uuidv5.URL); // ⇨ 'c106a26a-21bb-5538-8bf2-57095d1976c1'

uuid.validate(str)

Test a string to see if it is a valid UUID

Example:

javascript
import { validate as uuidValidate } from 'uuid';

uuidValidate('not a UUID'); // ⇨ false
uuidValidate('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'); // ⇨ true

Using validate and version together it is possible to do per-version validation, e.g. validate for only v4 UUIds.

javascript
import { version as uuidVersion } from 'uuid';
import { validate as uuidValidate } from 'uuid';

function uuidValidateV4(uuid) {
  return uuidValidate(uuid) && uuidVersion(uuid) === 4;
}

const v1Uuid = 'd9428888-122b-11e1-b85c-61cd3cbb3210';
const v4Uuid = '109156be-c4fb-41ea-b1b4-efe1671c5836';

uuidValidateV4(v4Uuid); // ⇨ true
uuidValidateV4(v1Uuid); // ⇨ false

uuid.version(str)

Detect RFC version of a UUID

Example:

javascript
import { version as uuidVersion } from 'uuid';

uuidVersion('45637ec4-c85f-11ea-87d0-0242ac130003'); // ⇨ 1
uuidVersion('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'); // ⇨ 4

Command Line

UUIDs can be generated from the command line using uuid.

shell
$ uuid
ddeb27fb-d9a0-4624-be4d-4615062daed4

The default is to generate version 4 UUIDS, however the other versions are supported. Type uuid --help for details:

shell
$ uuid --help

Usage:
  uuid
  uuid v1
  uuid v3 <name> <namespace uuid>
  uuid v4
  uuid v5 <name> <namespace uuid>
  uuid --help

Note: <namespace uuid> may be "URL" or "DNS" to use the corresponding UUIDs
defined by RFC4122

ECMAScript Modules

This library comes with ECMAScript Modules (ESM) support for Node.js versions that support it ([example](./examples/node-esmodules/)) as well as bundlers like rollup.js ([example](./examples/browser-rollup/)) and webpack ([example](./examples/browser-webpack/)) (targeting both, Node.js and browser environments).

javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'

To run the examples you must first create a dist build of this library in the module root:

shell
npm run build

CDN Builds

ECMAScript Modules

To load this module directly into modern browsers that support loading ECMAScript Modules you can make use of jspm:

html
<script type="module">
  import { v4 as uuidv4 } from 'https://jspm.dev/uuid';
  console.log(uuidv4()); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
</script>

UMD

To load this module directly into older browsers you can use the UMD (Universal Module Definition) builds from any of the following CDNs:

Using UNPKG:

html
<script src="https://unpkg.com/uuid@latest/dist/umd/uuidv4.min.js"></script>

Using jsDelivr:

html
<script src="https://cdn.jsdelivr.net/npm/uuid@latest/dist/umd/uuidv4.min.js"></script>

Using cdnjs:

html
<script src="https://cdnjs.cloudflare.com/ajax/libs/uuid/8.1.0/uuidv4.min.js"></script>

These CDNs all provide the same [uuidv4()](#uuidv4options-buffer-offset) method:

html
<script>
  uuidv4(); // ⇨ '55af1e37-0734-46d8-b070-a1e42e4fc392'
</script>

Methods for the other algorithms ([uuidv1()](#uuidv1options-buffer-offset), [uuidv3()](#uuidv3name-namespace-buffer-offset) and [uuidv5()](#uuidv5name-namespace-buffer-offset)) are available from the files uuidv1.min.js, uuidv3.min.js and uuidv5.min.js respectively.

"getRandomValues() not supported"

This error occurs in environments where the standard [crypto.getRandomValues()](https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues) API is not supported. This issue can be resolved by adding an appropriate polyfill:

React Native / Expo

1. Install [react-native-get-random-values](https://github.com/LinusU/react-native-get-random-values#readme)
2. Import it _before_ uuid. Since uuid might also appear as a transitive dependency of some other imports it's safest to just import react-native-get-random-values as the very first thing in your entry point:

javascript
import 'react-native-get-random-values';
import { v4 as uuidv4 } from 'uuid';

Note: If you are using Expo, you must be using at least react-native-get-random-values@1.5.0 and expo@39.0.0.

Web Workers / Service Workers (Edge <= 18)

In Edge <= 18, Web Crypto is not supported in Web Workers or Service Workers and we are not aware of a polyfill (let us know if you find one, please).

Upgrading From uuid@7.x

Only Named Exports Supported When Using with Node.js ESM

uuid@7.x did not come with native ECMAScript Module (ESM) support for Node.js. Importing it in Node.js ESM consequently imported the CommonJS source with a default export. This library now comes with true Node.js ESM support and only provides named exports.

Instead of doing:

javascript
import uuid from 'uuid';
uuid.v4();

you will now have to use the named exports:

javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4();

Deep Requires No Longer Supported

Deep requires like require('uuid/v4') [which have been deprecated in uuid@7.x](#deep-requires-now-deprecated) are no longer supported.

Upgrading From uuid@3.x

"_Wait... what happened to uuid@4.x - uuid@6.x?!?_"

In order to avoid confusion with RFC [version 4](#uuidv4options-buffer-offset) and [version 5](#uuidv5name-namespace-buffer-offset) UUIDs, and a possible version 6, releases 4 thru 6 of this module have been skipped.

Deep Requires Now Deprecated

uuid@3.x encouraged the use of deep requires to minimize the bundle size of browser builds:

javascript
const uuidv4 = require('uuid/v4'); // <== NOW DEPRECATED!
uuidv4();

As of uuid@7.x this library now provides ECMAScript modules builds, which allow packagers like Webpack and Rollup to do "tree-shaking" to remove dead code. Instead, use the import syntax:

javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4();

... or for CommonJS:

javascript
const { v4: uuidv4 } = require('uuid');
uuidv4();

Default Export Removed

uuid@3.x was exporting the Version 4 UUID method as a default export:

javascript
const uuid = require('uuid'); // <== REMOVED!

This usage pattern was already discouraged in uuid@3.x and has been removed in uuid@7.x.

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