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<!-- -- This file is auto-generated from README_js.md. Changes should be made there. -->uuid
For the creation of RFC9562 (formally RFC4122) UUIDs
- Complete - Support for all RFC9562 UUID versions
- Cross-platform - Support for ...
- CommonJS, ECMAScript Modules
- NodeJS 16+ (LTS releases)
- Chrome, Safari, Firefox, Edge browsers
- React Native / Expo
- Secure - Cryptographically-strong random values
- Compact - No dependencies, tree-shakable
- CLI - Includes the
uuid
command line utility - Typescript - Types now included
[!NOTE] w>
uuid@11
is now available: See the CHANGELOG for details. TL;DR:
- TypeScript support is now included (remove
@types/uuid
from your dependencies)- Subtle changes to how the
options
arg is interpreted forv1()
,v6()
, andv7()
. See details- Binary UUIDs are now
Uint8Array
s. (May impact callers ofparse()
,stringify()
, or that pass anoption#buf
argument tov1()
-v7()
.)
Quickstart
1. Install
npm install uuid
2. Create a UUID
ESM-syntax (must use named exports):
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
... CommonJS:
const { v4: uuidv4 } = require('uuid');
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
For timestamp UUIDs, namespace UUIDs, and other options read on ...
API Summary
uuid.NIL | The nil UUID string (all zeros) | New in uuid@8.3 |
uuid.MAX | The max UUID string (all ones) | New in uuid@9.1 |
uuid.parse() | Convert UUID string to array of bytes | New in uuid@8.3 |
uuid.stringify() | Convert array of bytes to UUID string | New in uuid@8.3 |
uuid.v1() | Create a version 1 (timestamp) UUID | |
uuid.v1ToV6() | Create a version 6 UUID from a version 1 UUID | New in uuid@10 |
uuid.v3() | Create a version 3 (namespace w/ MD5) UUID | |
uuid.v4() | Create a version 4 (random) UUID | |
uuid.v5() | Create a version 5 (namespace w/ SHA-1) UUID | |
uuid.v6() | Create a version 6 (timestamp, reordered) UUID | New in uuid@10 |
uuid.v6ToV1() | Create a version 1 UUID from a version 6 UUID | New in uuid@10 |
uuid.v7() | Create a version 7 (Unix Epoch time-based) UUID | New in uuid@10 |
uuid.v8() | "Intentionally left blank" | |
uuid.validate() | Test a string to see if it is a valid UUID | New in uuid@8.3 |
uuid.version() | Detect RFC version of a UUID | New in uuid@8.3 |
API
uuid.NIL
The nil UUID string (all zeros).
Example:
import { NIL as NIL_UUID } from 'uuid';
NIL_UUID; // ⇨ '00000000-0000-0000-0000-000000000000'
uuid.MAX
The max UUID string (all ones).
Example:
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()
andstringify()
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
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()
andstringify()
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 = 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 ] | 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 |
<!-- prettier-ignore -->[!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
andoptions.rng
are only meaningful on the very first call tov1()
, where they may be passed to initialize the internalnode
andclockseq
fields.
Example:
import { v1 as uuidv1 } from 'uuid';
uuidv1(); // ⇨ '2c5ea4c0-4067-11e9-9bdd-2b0d7b3dcb6d'
Example using options
:
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
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 ] | 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(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
Example using predefined random
values:
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 ] | 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
andURL
namespaces are available asv5.DNS
andv5.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'
uuid.v6([options[, buffer[, offset]]])
Create an RFC version 6 (timestamp, reordered) UUID
This method takes the same arguments as uuid.v1().
import { v6 as uuidv6 } from 'uuid';
uuidv6(); // ⇨ '1e940672-c5ea-64c0-9b5d-ab8dfbbd4bed'
Example using options
:
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
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 insure uniqueness for UUIDs generated within the same millisecond time interval. Default = random value. |
[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 { v7 as uuidv7 } from 'uuid';
uuidv7(); // ⇨ '01695553-c90c-705a-b56d-778dfbbd4bed'
uuid.v8()
"Intentionally left blank"
<!-- prettier-ignore -->[!NOTE] Version 8 (experimental) UUIDs are "for experimental or vendor-specific use cases". The RFC does not define a creation algorithm for them, which is why this package does not offer a
v8()
method. Thevalidate()
andversion()
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:
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
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
<!-- prettier-ignore -->
[!NOTE] This method returns
0
for theNIL
UUID, and15
for theMAX
UUID.
Command Line
UUIDs can be generated from the command line using uuid
.
$ 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:
$ npx uuid --help
Usage:
uuid
uuid v1
uuid v3 <name> <namespace uuid>
uuid v4
uuid v5 <name> <namespace uuid>
uuid v7
uuid --help
Note: <namespace uuid> 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 insure 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.
Known issues
React Native / Expo
- Install
react-native-get-random-values
- Import it before
uuid
. Sinceuuid
might also appear as a transitive dependency of some other imports it's safest to just importreact-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';
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