For the creation of RFC4122 UUIDs
- Complete - Support for RFC4122 version 1, 3, 4, and 5 UUIDs
- Cross-platform - Support for ...
- CommonJS, ECMAScript Modules and UMD builds
- Node 8, 10, 12
- Chrome, Safari, Firefox, Edge, IE 11 browsers
- Webpack and rollup.js module bundlers
- Secure - Cryptographically-strong random values
- Small - Zero-dependency, small footprint, plays nice with "tree shaking" packagers
- CLI - Includes the
uuid
command line utility
Upgrading from uuid@3? Your code is probably okay, but check out Upgrading From uuid@3 for details.
npm install uuid
Once installed, decide which type of UUID you need. RFC4122 provides for four versions, all of which are supported here. In order of popularity, they are:
- Version 4 (random) - Created from cryptographically-strong random values
- Version 1 (timestamp) - Created from the system clock (plus random values)
- Version 5 (namespace, SHA-1) - Created from user-supplied name and namespace strings
- Version 3 (namespace, MD5) - Like version 5, above, but with a poorer hash algorithm
Unsure which one to use? Use version 4 (random) unless you have a specific need for one of the other versions. See also this FAQ.
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
import { v1 as uuidv1 } from 'uuid';
uuidv1(); // ⇨ '2c5ea4c0-4067-11e9-8b2d-1b9d6bcdbbfd'
import { v5 as uuidv5 } from 'uuid'; // For version 5
import { v3 as uuidv3 } from 'uuid'; // For version 3
// Using predefined DNS namespace (for domain names)
uuidv5('hello.example.com', uuidv5.DNS); // ⇨ 'fdda765f-fc57-5604-a269-52a7df8164ec'
uuidv3('hello.example.com', uuidv3.DNS); // ⇨ '9125a8dc-52ee-365b-a5aa-81b0b3681cf6'
// Using predefined URL namespace (for URLs)
uuidv5('http://example.com/hello', uuidv5.URL); // ⇨ '3bbcee75-cecc-5b56-8031-b6641c1ed1f1'
uuidv3('http://example.com/hello', uuidv3.URL); // ⇨ 'c6235813-3ba4-3801-ae84-e0a6ebb7d138'
// Using a custom namespace (See note, above, about generating your own
// namespace UUID)
const MY_NAMESPACE = '1b671a64-40d5-491e-99b0-da01ff1f3341';
uuidv5('Hello, World!', MY_NAMESPACE); // ⇨ '630eb68f-e0fa-5ecc-887a-7c7a62614681'
uuidv3('Hello, World!', MY_NAMESPACE); // ⇨ 'e8b5a51d-11c8-3310-a6ab-367563f20686'
import { v4 as uuidv4 } from 'uuid';
// Incantations
uuidv4();
uuidv4(options);
uuidv4(options, buffer, offset);
Generate and return a RFC4122 version 4 UUID.
options
- (Object) Optional uuid state to apply. Properties may include:random
- (Number[16]) Array of 16 numbers (0-255) to use in place of randomly generated values. Takes precedence overoptions.rng
.rng
- (Function) Random # generator function that returns an Array[16] of byte values (0-255). Alternative tooptions.random
.
buffer
- (Array | Buffer) Array or buffer where UUID bytes are to be written.offset
- (Number) Starting index inbuffer
at which to begin writing.
Returns buffer
, if specified, otherwise the string form of the UUID
Example: Generate string UUID with predefined random
values
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'
Example: Generate two IDs in a single buffer
const buffer = new Array();
uuidv4(null, buffer, 0); // ⇨
// [
// 155, 29, 235, 77, 59,
// 125, 75, 173, 155, 221,
// 43, 13, 123, 61, 203,
// 109
// ]
uuidv4(null, buffer, 16); // ⇨
// [
// 155, 29, 235, 77, 59, 125, 75, 173,
// 155, 221, 43, 13, 123, 61, 203, 109,
// 27, 157, 107, 205, 187, 253, 75, 45,
// 155, 93, 171, 141, 251, 189, 75, 237
// ]
import { v1 as uuidv1 } from 'uuid';
// Incantations
uuidv1();
uuidv1(options);
uuidv1(options, buffer, offset);
Generate and return a RFC4122 version 1 (timestamp) UUID.
options
- (Object) Optional uuid state to apply. Properties may include:node
- (Array) Node id as Array of 6 bytes (per 4.1.6). Default: Randomly generated ID. See note 1.clockseq
- (Number between 0 - 0x3fff) RFC clock sequence. Default: An internally maintained clockseq is used.msecs
- (Number) Time in milliseconds since unix Epoch. Default: The current time is used.nsecs
- (Number between 0-9999) additional time, in 100-nanosecond units. Ignored ifmsecs
is unspecified. Default: internal uuid counter is used, as per 4.2.1.2.random
- (Number[16]) Array of 16 numbers (0-255) to use for initialization ofnode
andclockseq
as described above. Takes precedence overoptions.rng
.rng
- (Function) Random # generator function that returns an Array[16] of byte values (0-255). Alternative tooptions.random
.
buffer
- (Array | Buffer) Array or buffer where UUID bytes are to be written.offset
- (Number) Starting index inbuffer
at which to begin writing.
Returns buffer
, if specified, otherwise the string form of the 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.
Example: Generate string UUID with fully-specified options
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'
Example: In-place generation of two binary IDs
// Generate two ids in an array
const arr = new Array();
uuidv1(null, arr, 0); // ⇨
// [
// 44, 94, 164, 192, 64,
// 103, 17, 233, 146, 52,
// 27, 157, 107, 205, 187,
// 253
// ]
uuidv1(null, arr, 16); // ⇨
// [
// 44, 94, 164, 192, 64, 103, 17, 233,
// 146, 52, 27, 157, 107, 205, 187, 253,
// 44, 94, 164, 193, 64, 103, 17, 233,
// 146, 52, 27, 157, 107, 205, 187, 253
// ]
import { v5 as uuidv5 } from 'uuid';
// Incantations
uuidv5(name, namespace);
uuidv5(name, namespace, buffer);
uuidv5(name, namespace, buffer, offset);
Generate and return a RFC4122 version 5 UUID.
name
- (String | Array[]) "name" to create UUID withnamespace
- (String | Array[]) "namespace" UUID either as a String or Array[16] of byte valuesbuffer
- (Array | Buffer) Array or buffer where UUID bytes are to be written.offset
- (Number) Starting index inbuffer
at which to begin writing. Default = 0
Returns buffer
, if specified, otherwise the string form of the UUID
Example:
uuidv5('hello world', MY_NAMESPACE); // ⇨ '9f282611-e0fd-5650-8953-89c8e342da0b'
import { v3 as uuidv3 } from 'uuid';
// Incantations
uuidv3(name, namespace);
uuidv3(name, namespace, buffer);
uuidv3(name, namespace, buffer, offset);
Generate and return a RFC4122 version 3 UUID.
name
- (String | Array[]) "name" to create UUID withnamespace
- (String | Array[]) "namespace" UUID either as a String or Array[16] of byte valuesbuffer
- (Array | Buffer) Array or buffer where UUID bytes are to be written.offset
- (Number) Starting index inbuffer
at which to begin writing. Default = 0
Returns buffer
, if specified, otherwise the string form of the UUID
Example:
uuidv3('hello world', MY_NAMESPACE); // ⇨ '042ffd34-d989-321c-ad06-f60826172424'
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
For usage in the browser uuid
provides support for ECMAScript
Modules (ESM) that enable
tree-shaking for bundlers, like rollup.js
(example) and webpack
(example).
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
There is experimental native ESM support for the browser but it should not be considered ready for production use and may change or disappear in future releases.
To run the examples you must first create a dist build of this library in the module root:
npm run build
If you want to load a minified UMD build directly in the browser you can use one of the popular npm CDNs:
<script src="https://unpkg.com/uuid@latest/dist/umd/uuidv4.min.js"></script>
<script>
alert(uuidv4());
</script>
or
<script src="https://cdn.jsdelivr.net/npm/uuid@latest/dist/umd/uuidv4.min.js"></script>
<script>
alert(uuidv4());
</script>
Available bundles:
"Wait... what happened to uuid@4 - uuid@6?!?"
In order to avoid confusion with RFC version 4 and version 5 UUIDs, and a possible version 6, releases 4 thru 6 of this module have been skipped. Hence, how we're now at uuid@7.
uuid@3 encouraged the use of deep requires to minimize the bundle size of browser builds:
const uuidv4 = require('uuid/v4'); // <== DEPRECATED!
uuidv4();
As of uuid@7 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();
The Version 4 UUID method, v4()
is no longer available as the default export. This usage pattern was deprecated in uuid@3.1 and has been removed in uuid@7.
Instead, require/import the exported v4
property, as noted above.
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