# uuid [![CI](https://github.com/uuidjs/uuid/workflows/CI/badge.svg)](https://github.com/uuidjs/uuid/actions?query=workflow%3ACI) [![Browser](https://github.com/uuidjs/uuid/workflows/Browser/badge.svg)](https://github.com/uuidjs/uuid/actions/workflows/browser.yml) For the creation of [RFC9562](https://www.rfc-editor.org/rfc/rfc9562.html) (formerly [RFC4122](https://www.rfc-editor.org/rfc/rfc4122.html)) UUIDs - **Complete** - Support for all RFC9562 UUID versions - **Cross-platform** - Support for... - [Typescript](#support) - [Chrome, Safari, Firefox, and Edge](#support) - [NodeJS](#support) - [React Native / Expo](#react-native--expo) - **Secure** - Uses modern `crypto` API for random values - **Compact** - Zero-dependency, [tree-shakable](https://developer.mozilla.org/en-US/docs/Glossary/Tree_shaking) - **CLI** - [`uuid` command line](#command-line) utility > [!NOTE] > > Starting with `uuid@12` CommonJS is no longer supported. See [implications](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c) and [motivation](https://github.com/uuidjs/uuid/issues/881) for details. ## Quickstart **1. Install** ```shell npm install uuid ``` **2. Create a UUID** ```javascript import { v4 as uuidv4 } from "uuid"; uuidv4(); // ⇨ 'ab16e731-6cee-424d-81a0-5929e9bdb0cc' ``` For timestamp UUIDs, namespace UUIDs, and other options read on ... ## API Summary | | | | | -------------------------------------------------- | ----------------------------------------------- | ----------------- | | [`uuid.NIL`](#uuidnil) | The nil UUID string (all zeros) | New in `uuid@8.3` | | [`uuid.MAX`](#uuidmax) | The max UUID string (all ones) | New in `uuid@9.1` | | [`uuid.parse()`](#uuidparsestr) | Convert UUID string to array of bytes | New in `uuid@8.3` | | [`uuid.stringify()`](#uuidstringifyarr-offset) | Convert array of bytes to UUID string | New in `uuid@8.3` | | [`uuid.v1()`](#uuidv1options-buffer-offset) | Create a version 1 (timestamp) UUID | | | [`uuid.v1ToV6()`](#uuidv1tov6uuid) | Create a version 6 UUID from a version 1 UUID | New in `uuid@10` | | [`uuid.v3()`](#uuidv3name-namespace-buffer-offset) | Create a version 3 (namespace w/ MD5) UUID | | | [`uuid.v4()`](#uuidv4options-buffer-offset) | Create a version 4 (random) UUID | | | [`uuid.v5()`](#uuidv5name-namespace-buffer-offset) | Create a version 5 (namespace w/ SHA-1) UUID | | | [`uuid.v6()`](#uuidv6options-buffer-offset) | Create a version 6 (timestamp, reordered) UUID | New in `uuid@10` | | [`uuid.v6ToV1()`](#uuidv6tov1uuid) | Create a version 1 UUID from a version 6 UUID | New in `uuid@10` | | [`uuid.v7()`](#uuidv7options-buffer-offset) | Create a version 7 (Unix Epoch time-based) UUID | New in `uuid@10` | | ~~[`uuid.v8()`](#uuidv8)~~ | "Intentionally left blank" | | | [`uuid.validate()`](#uuidvalidatestr) | Test a string to see if it is a valid UUID | New in `uuid@8.3` | | [`uuid.version()`](#uuidversionstr) | Detect RFC version of a UUID | New in `uuid@8.3` | ## 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.MAX The max UUID string (all ones). Example: ```javascript import { MAX as MAX_UUID } from "uuid"; MAX_UUID; // ⇨ 'ffffffff-ffff-ffff-ffff-ffffffffffff' ``` ### 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: ```javascript import { parse as uuidParse } from "uuid"; // Parse a UUID uuidParse("6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b"); // ⇨ // Uint8Array(16) [ // 110, 192, 189, 127, 17, // 192, 67, 218, 151, 94, // 42, 138, 217, 235, 174, // 11 // ] ``` ### 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: ```javascript import { stringify as uuidStringify } from "uuid"; const uuidBytes = Uint8Array.of( 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 | | | | ---------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- | | [`options`] | `Object` with one or more of the following properties: | | [`options.node = (random)` ] | RFC "node" field as an `Array[6]` of byte values (per 4.1.6) | | [`options.clockseq = (random)`] | RFC "clock sequence" as a `Number` between 0 - 0x3fff | | [`options.msecs = (current time)`] | RFC "timestamp" field (`Number` of milliseconds, unix epoch) | | [`options.nsecs = 0`] | RFC "timestamp" field (`Number` of nanoseconds to add to `msecs`, should be 0-10,000) | | [`options.random = (random)`] | `Array` of 16 random bytes (0-255) used to generate other fields, above | | [`options.rng`] | Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255) | | [`buffer`] | `Uint8Array` or `Uint8Array` subtype (e.g. Node.js `Buffer`). If provided, binary UUID is written into the array, 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 | Example: ```javascript import { v1 as uuidv1 } from "uuid"; uuidv1(); // ⇨ '4d9d2960-31d0-11f1-aba8-29728d41eeed' ``` Example using `options`: ```javascript import { v1 as uuidv1 } from "uuid"; const options = { node: Uint8Array.of(0x01, 0x23, 0x45, 0x67, 0x89, 0xab), clockseq: 0x1234, msecs: new Date("2011-11-01").getTime(), nsecs: 5678, }; uuidv1(options); // ⇨ '710b962e-041c-11e1-9234-0123456789ab' ``` ### uuid.v1ToV6(uuid) Convert a UUID from version 1 to version 6 ```javascript import { v1ToV6 } from "uuid"; v1ToV6("92f62d9e-22c4-11ef-97e9-325096b39f47"); // ⇨ '1ef22c49-2f62-6d9e-97e9-325096b39f47' ``` ### uuid.v3(name, namespace[, buffer[, offset]]) Create an RFC version 3 (namespace w/ MD5) UUID API is identical to `v5()`, but uses "v3" instead. > [!IMPORTANT] > 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 | | | | ------------------ | -------------------------------------------------------------------------------------------------------------------------------------- | | [`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`] | `Uint8Array` or `Uint8Array` subtype (e.g. Node.js `Buffer`). If provided, binary UUID is written into the array, 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: ```javascript import { v4 as uuidv4 } from "uuid"; uuidv4(); // ⇨ '7934256a-bc92-4b69-b240-f9e463881aea' ``` Example using predefined `random` values: ```javascript import { v4 as uuidv4 } from "uuid"; const v4options = { random: Uint8Array.of( 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 | | | | -------------- | -------------------------------------------------------------------------------------------------------------------------------------- | | `name` | `String \| Array` | | `namespace` | `String \| Array[16]` Namespace UUID | | [`buffer`] | `Uint8Array` or `Uint8Array` subtype (e.g. Node.js `Buffer`). If provided, binary UUID is written into the array, 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: ```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.v6([options[, buffer[, offset]]]) Create an RFC version 6 (timestamp, reordered) UUID This method takes the same arguments as uuid.v1(). ```javascript import { v6 as uuidv6 } from "uuid"; uuidv6(); // ⇨ '1f131d04-d9dc-65a0-9516-5be66631ce97' ``` Example using `options`: ```javascript import { v6 as uuidv6 } from "uuid"; const options = { node: [0x01, 0x23, 0x45, 0x67, 0x89, 0xab], clockseq: 0x1234, msecs: new Date("2011-11-01").getTime(), nsecs: 5678, }; uuidv6(options); // ⇨ '1e1041c7-10b9-662e-9234-0123456789ab' ``` ### uuid.v6ToV1(uuid) Convert a UUID from version 6 to version 1 ```javascript import { v6ToV1 } from "uuid"; v6ToV1("1ef22c49-2f62-6d9e-97e9-325096b39f47"); // ⇨ '92f62d9e-22c4-11ef-97e9-325096b39f47' ``` ### uuid.v7([options[, buffer[, offset]]]) Create an RFC version 7 (random) UUID | | | | ---------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`options`] | `Object` with one or more of the following properties: | | [`options.msecs = (current time)`] | RFC "timestamp" field (`Number` of milliseconds, unix epoch) | | [`options.random = (random)`] | `Array` of 16 random bytes (0-255) used to generate other fields, above | | [`options.rng`] | Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255) | | [`options.seq = (random)`] | 32-bit sequence `Number` between 0 - 0xffffffff. This may be provided to help ensure uniqueness for UUIDs generated within the same millisecond time interval. Default = random value. | | [`buffer`] | `Uint8Array` or `Uint8Array` subtype (e.g. Node.js `Buffer`). If provided, binary UUID is written into the array, 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: ```javascript import { v7 as uuidv7 } from "uuid"; uuidv7(); // ⇨ '019d637c-c6fb-74e9-8b9d-2f1d459a4201' ``` ### ~~uuid.v8()~~ **_"Intentionally left blank"_** > [!NOTE] > Version 8 (experimental) UUIDs are "[for experimental or vendor-specific use cases](https://www.rfc-editor.org/rfc/rfc9562.html#name-uuid-version-8)". The RFC does not define a creation algorithm for them, which is why this package does not offer a `v8()` method. The `validate()` and `version()` methods do work with such UUIDs, however. ### 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: ```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 | | | | --------- | ---------------------------------------- | | `str` | A valid UUID `String` | | _returns_ | `Number` The RFC version of the UUID | | _throws_ | `TypeError` if `str` is not a valid UUID | Example: ```javascript import { version as uuidVersion } from "uuid"; uuidVersion("45637ec4-c85f-11ea-87d0-0242ac130003"); // ⇨ 1 uuidVersion("6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b"); // ⇨ 4 ``` > [!NOTE] > This method returns `0` for the `NIL` UUID, and `15` for the `MAX` UUID. ## Command Line UUIDs can be generated from the command line using `uuid`. ```shell $ npx 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 $ npx uuid --help Usage: uuid uuid v1 uuid v3 uuid v4 uuid v5 uuid v7 uuid --help Note: may be "URL" or "DNS" to use the corresponding UUIDs defined by RFC9562 ``` ## `options` Handling for Timestamp UUIDs Prior to `uuid@11`, it was possible for `options` state to interfere with the internal state used to ensure uniqueness of timestamp-based UUIDs (the `v1()`, `v6()`, and `v7()` methods). Starting with `uuid@11`, this issue has been addressed by using the presence of the `options` argument as a flag to select between two possible behaviors: - Without `options`: Internal state is utilized to improve UUID uniqueness. - With `options`: Internal state is **NOT** used and, instead, appropriate defaults are applied as needed. ## Support **Browsers**: `uuid` [builds are tested](/uuidjs/uuid/blob/main/wdio.conf.js) against the latest version of desktop Chrome, Safari, Firefox, and Edge. Mobile versions of these same browsers are expected to work but aren't currently tested. **Node**: `uuid` [builds are tested](https://github.com/uuidjs/uuid/blob/main/.github/workflows/ci.yml#L26-L27) against node ([LTS releases](https://github.com/nodejs/Release)), plus one prior. E.g. At the time of this writing `node@20` is the "maintenance" release and `node@24` is the "current" release, so `uuid` supports `node@20`-`node@24`. **Typescript**: TS versions released within the past two years are supported. [source](https://github.com/microsoft/TypeScript/issues/49088#issuecomment-2468723715) ## Known issues ### "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) 1. 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"; ``` --- Markdown generated from [README_js.md](README_js.md) by

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zip	dist/	4096	---	2026-06-06 17:49:09
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-	README.md	21302	md	2026-06-06 17:49:09
-	package.json	3453	json	2026-06-06 17:49:09

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