UUID

[npm UUID] #uuid for nodejs apps

 # UUID 
 
For the creation of [RFC4122](http://www.ietf.org/rfc/rfc4122.txt) UUIDs.   Via NodeJS module from NPM.

-   **Complete** - Support for RFC4122 version 1, 3, 4, and 5 UUIDs
-   **Cross-platform** - Support for ...
    -   CommonJS, [ECMAScript Modules](https://www.npmjs.com/package/uuid#ecmascript-modules) and [CDN builds](https://www.npmjs.com/package/uuid#cdn-builds)
    -   Node 8, 10, 12, 14
    -   Chrome, Safari, Firefox, Edge, IE 11 browsers
    -   Webpack and rollup.js module bundlers
    -   [React Native / Expo](https://www.npmjs.com/package/uuid#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](https://www.npmjs.com/package/uuid#command-line) utility

**Upgrading from `[email protected]`?** Your code is probably okay, but check out [Upgrading From `[email protected]`](https://www.npmjs.com/package/uuid#upgrading-from-uuid3x) for details.

## [](https://www.npmjs.com/package/uuid#quickstart)Quickstart

To create a random UUID...

**1. Install**

npm install uuid

**2. Create a UUID** (ES6 module syntax)
```
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
```
... or using CommonJS syntax:
```
const { v4: uuidv4 } = require('uuid');
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
```
For timestamp UUIDs, namespace UUIDs, and other options read on ...

## [](https://www.npmjs.com/package/uuid#api-summary)API Summary

[`uuid.NIL`](https://www.npmjs.com/package/uuid#uuidnil)

The nil UUID string (all zeros)

New in `[email protected]`

[`uuid.parse()`](https://www.npmjs.com/package/uuid#uuidparsestr)

Convert UUID string to array of bytes

New in `[email protected]`

[`uuid.stringify()`](https://www.npmjs.com/package/uuid#uuidstringifyarr-offset)

Convert array of bytes to UUID string

New in `[email protected]`

[`uuid.v1()`](https://www.npmjs.com/package/uuid#uuidv1options-buffer-offset)

Create a version 1 (timestamp) UUID

[`uuid.v3()`](https://www.npmjs.com/package/uuid#uuidv3name-namespace-buffer-offset)

Create a version 3 (namespace w/ MD5) UUID

[`uuid.v4()`](https://www.npmjs.com/package/uuid#uuidv4options-buffer-offset)

Create a version 4 (random) UUID

[`uuid.v5()`](https://www.npmjs.com/package/uuid#uuidv5name-namespace-buffer-offset)

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

[`uuid.validate()`](https://www.npmjs.com/package/uuid#uuidvalidatestr)

Test a string to see if it is a valid UUID

New in `[email protected]`

[`uuid.version()`](https://www.npmjs.com/package/uuid#uuidversionstr)

Detect RFC version of a UUID

New in `[email protected]`

## [](https://www.npmjs.com/package/uuid#api)API

### [](https://www.npmjs.com/package/uuid#uuidnil)uuid.NIL

The nil UUID string (all zeros).

Example:

import { NIL as NIL_UUID } from 'uuid';

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

### [](https://www.npmjs.com/package/uuid#uuidparsestr)uuid.parse(str)

Convert UUID string to array of bytes

`str`

A valid UUID `String`

_returns_

`Uint8Array[16]`

_throws_

`TypeError` if `str` is not a valid UUID

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

Example:
```
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'
  // ]
```
### [](https://www.npmjs.com/package/uuid#uuidstringifyarr-offset)uuid.stringify(arr[, offset])

Convert array of bytes to UUID string

`arr`

`Array`-like collection of 16 values (starting from `offset`) between 0-255.

[`offset` = 0]

`Number` Starting index in the Array

_returns_

`String`

_throws_

`TypeError` if a valid UUID string cannot be generated

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

Example:
```
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'
```
### [](https://www.npmjs.com/package/uuid#uuidv1options-buffer-offset)uuid.v1([options[, buffer[, offset]]])

Create an RFC version 1 (timestamp) UUID

[`options`]

`Object` with one or more of the following properties:

[`options.node` ]

RFC "node" field as an `Array[6]` of byte values (per 4.1.6)

[`options.clockseq`]

RFC "clock sequence" as a `Number` between 0 - 0x3fff

[`options.msecs`]

RFC "timestamp" field (`Number` of milliseconds, unix epoch)

[`options.nsecs`]

RFC "timestamp" field (`Number` of nanseconds to add to `msecs`, should be 0-10,000)

[`options.random`]

`Array` of 16 random bytes (0-255)

[`options.rng`]

Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255)

[`buffer`]

`Array | Buffer` If specified, uuid will be written here in byte-form, starting at `offset`

[`offset` = 0]

`Number` Index to start writing UUID bytes in `buffer`

_returns_

UUID `String` if no `buffer` is specified, otherwise returns `buffer`

_throws_

`Error` if more than 10M UUIDs/sec are requested

Note: The default [node id](https://tools.ietf.org/html/rfc4122#section-4.1.6) (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:

import { v1 as uuidv1 } from 'uuid';

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

Example using `options`:
```
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'
```
### [](https://www.npmjs.com/package/uuid#uuidv3name-namespace-buffer-offset)uuid.v3(name, namespace[, buffer[, offset]])

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

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

⚠️ Note: Per the RFC, "_If backward compatibility is not an issue, SHA-1 [Version 5] is preferred_."

### [](https://www.npmjs.com/package/uuid#uuidv4options-buffer-offset)uuid.v4([options[, buffer[, offset]]])

Create an RFC version 4 (random) UUID

[`options`]

`Object` with one or more of the following properties:

[`options.random`]

`Array` of 16 random bytes (0-255)

[`options.rng`]

Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255)

[`buffer`]

`Array | Buffer` If specified, uuid will be written here in byte-form, starting at `offset`

[`offset` = 0]

`Number` Index to start writing UUID bytes in `buffer`

_returns_

UUID `String` if no `buffer` is specified, otherwise returns `buffer`

Example:

import { v4 as uuidv4 } from 'uuid';

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

Example using predefined `random` values:
```
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'
```
### [](https://www.npmjs.com/package/uuid#uuidv5name-namespace-buffer-offset)uuid.v5(name, namespace[, buffer[, offset]])

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

`name`

`String | Array`

`namespace`

`String | Array[16]` Namespace UUID

[`buffer`]

`Array | Buffer` If specified, uuid will be written here in byte-form, starting at `offset`

[`offset` = 0]

`Number` Index to start writing UUID bytes in `buffer`

_returns_

UUID `String` if no `buffer` is specified, otherwise returns `buffer`

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

Example with custom namespace:

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:

import { v5 as uuidv5 } from 'uuid';

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

### [](https://www.npmjs.com/package/uuid#uuidvalidatestr)uuid.validate(str)
```
Test a string to see if it is a valid UUID

`str`

`String` to validate

_returns_

`true` if string is a valid UUID, `false` otherwise

Example:

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.

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

### [](https://www.npmjs.com/package/uuid#uuidversionstr)uuid.version(str)

Detect RFC version of a UUID

`str`

A valid UUID `String`

_returns_

`Number` The RFC version of the UUID

_throws_

`TypeError` if `str` is not a valid UUID

Example:

import { version as uuidVersion } from 'uuid';

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

## [](https://www.npmjs.com/package/uuid#command-line)Command Line

UUIDs can be generated from the command line using `uuid`.

$ 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:

$ 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

## [](https://www.npmjs.com/package/uuid#ecmascript-modules)ECMAScript Modules

This library comes with [ECMAScript Modules](https://www.ecma-international.org/ecma-262/6.0/#sec-modules) (ESM) support for Node.js versions that support it ([example](https://github.com/uuidjs/uuid/blob/HEAD/examples/node-esmodules/)) as well as bundlers like [rollup.js](https://rollupjs.org/guide/en/#tree-shaking) ([example](https://github.com/uuidjs/uuid/blob/HEAD/examples/browser-rollup/)) and [webpack](https://webpack.js.org/guides/tree-shaking/) ([example](https://github.com/uuidjs/uuid/blob/HEAD/examples/browser-webpack/)) (targeting both, Node.js and browser environments).

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:

npm run build

## [](https://www.npmjs.com/package/uuid#cdn-builds)CDN Builds

### [](https://www.npmjs.com/package/uuid#ecmascript-modules-1)ECMAScript Modules

To load this module directly into modern browsers that [support loading ECMAScript Modules](https://caniuse.com/#feat=es6-module) you can make use of [jspm](https://jspm.org/):

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

### [](https://www.npmjs.com/package/uuid#umd)UMD

To load this module directly into older browsers you can use the [UMD (Universal Module Definition)](https://github.com/umdjs/umd) builds from any of the following CDNs:

**Using [UNPKG](https://unpkg.com/uuid@latest/dist/umd/)**:

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

**Using [jsDelivr](https://cdn.jsdelivr.net/npm/uuid@latest/dist/umd/)**:

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

**Using [cdnjs](https://cdnjs.com/libraries/uuid)**:

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

These CDNs all provide the same [`uuidv4()`](https://www.npmjs.com/package/uuid#uuidv4options-buffer-offset) method:

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

Methods for the other algorithms ([`uuidv1()`](https://www.npmjs.com/package/uuid#uuidv1options-buffer-offset), [`uuidv3()`](https://www.npmjs.com/package/uuid#uuidv3name-namespace-buffer-offset) and [`uuidv5()`](https://www.npmjs.com/package/uuid#uuidv5name-namespace-buffer-offset)) are available from the files `uuidv1.min.js`, `uuidv3.min.js` and `uuidv5.min.js` respectively.

## [](https://www.npmjs.com/package/uuid#getrandomvalues-not-supported)"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:

### [](https://www.npmjs.com/package/uuid#react-native--expo)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:

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

Note: If you are using Expo, you must be using at least `[email protected]` and `[email protected]`.

### [](https://www.npmjs.com/package/uuid#web-workers--service-workers-edge--18)Web Workers / Service Workers (Edge <= 18)

[In Edge <= 18, Web Crypto is not supported in Web Workers or Service Workers](https://caniuse.com/#feat=cryptography) and we are not aware of a polyfill (let us know if you find one, please).

## [](https://www.npmjs.com/package/uuid#upgrading-from-uuid7x)Upgrading From `[email protected]`

### [](https://www.npmjs.com/package/uuid#only-named-exports-supported-when-using-with-nodejs-esm)Only Named Exports Supported When Using with Node.js ESM

`[email protected]` 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:
```
import uuid from 'uuid';
uuid.v4();
```
you will now have to use the named exports:
```
import { v4 as uuidv4 } from 'uuid';
uuidv4();
```
### [](https://www.npmjs.com/package/uuid#deep-requires-no-longer-supported)Deep Requires No Longer Supported

Deep requires like `require('uuid/v4')` [which have been deprecated in `[email protected]`](https://www.npmjs.com/package/uuid#deep-requires-now-deprecated) are no longer supported.

## [](https://www.npmjs.com/package/uuid#upgrading-from-uuid3x)Upgrading From `[email protected]`

"_Wait... what happened to `[email protected]` - `[email protected]`?!?_"

In order to avoid confusion with RFC [version 4](https://www.npmjs.com/package/uuid#uuidv4options-buffer-offset) and [version 5](https://www.npmjs.com/package/uuid#uuidv5name-namespace-buffer-offset) UUIDs, and a possible [version 6](http://gh.peabody.io/uuidv6/), releases 4 thru 6 of this module have been skipped.

### [](https://www.npmjs.com/package/uuid#deep-requires-now-deprecated)Deep Requires Now Deprecated

`[email protected]` encouraged the use of deep requires to minimize the bundle size of browser builds:
```
const uuidv4 = require('uuid/v4'); // <== NOW DEPRECATED!
uuidv4();
```
As of `[email protected]` 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:

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

... or for CommonJS:

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

### [](https://www.npmjs.com/package/uuid#default-export-removed)Default Export Removed

`[email protected]` was exporting the Version 4 UUID method as a default export:

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

This usage pattern was already discouraged in `[email protected]` and has been removed in `[email protected]`.

----------

Markdown generated from [README_js.md](https://github.com/uuidjs/uuid/blob/HEAD/README_js.md) by [![RunMD Logo](https://camo.githubusercontent.com/9468a34345e7bbd42bae704e491c3b286542aa80d1bcf33dd3cd7801e0de4f7e/687474703a2f2f692e696d6775722e636f6d2f68304656797a552e706e67)](https://github.com/broofa/runmd)

## Keywords

-   [uuid](https://www.npmjs.com/search?q=keywords:uuid)
-   [guid](https://www.npmjs.com/search?q=keywords:guid)
-   [rfc4122](https://www.npmjs.com/search?q=keywords:rfc4122)

### Install

`npm i uuid`

### Repository

[github.com/uuidjs/uuid](https://github.com/uuidjs/uuid)

### Homepage

[github.com/uuidjs/uuid#readme](https://github.com/uuidjs/uuid#readme)

### Weekly Downloads

74,514,248

### Version

8.3.2