Simple, fast generation of RFC4122 UUIDS.

Features:

• Support for version 1, 4 and 5 UUIDs
• Cross-platform
• Uses cryptographically-strong random number APIs (when available)
• Zero-dependency, small footprint (... but not this small)

npm install uuid

Then generate your uuid version of choice ...

Version 1 (timestamp):

const uuidv1 = require('uuid/v1');
uuidv1(); // -> '6c84fb90-12c4-11e1-840d-7b25c5ee775a'

Version 4 (random):

const uuidv4 = require('uuid/v4');
uuidv4(); // -> '110ec58a-a0f2-4ac4-8393-c866d813b8d1'

Version 5 (namespace):

const uuidv5 = require('uuid/v5');

// ... using predefined DNS namespace (for domain names)
uuidv5('hello.example.com', uuidv5.DNS)); // -> 'fdda765f-fc57-5604-a269-52a7df8164ec'

// ... using predefined URL namespace (for, well, URLs)
uuidv5('http://example.com/hello', uuidv5.URL); // -> '3bbcee75-cecc-5b56-8031-b6641c1ed1f1'

// ... using a custom namespace
const MY_NAMESPACE = '<UUID string you previously generated elsewhere>';
uuidv5('Hello, World!', MY_NAMESPACE); // -> '90123e1c-7512-523e-bb28-76fab9f2f73d'

Browser-ready versions of this module are available via wzrd.in.

For version 1 uuids:

<script src="http://wzrd.in/standalone/uuid%2Fv1@latest"></script>
<script>
uuidv1(); // -> v1 UUID
</script>

For version 4 uuids:

<script src="http://wzrd.in/standalone/uuid%2Fv4@latest"></script>
<script>
uuidv4(); // -> v4 UUID
</script>

For version 5 uuids:

<script src="http://wzrd.in/standalone/uuid%2Fv5@latest"></script>
<script>
uuidv5('http://example.com/hello', uuidv5.URL); // -> v5 UUID
</script>

const uuidv1 = require('uuid/v1');

// Allowed arguments
uuidv1();
uuidv1(options);
uuidv1(options, buffer, offset);

Generate and return a RFC4122 v1 (timestamp-based) 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 | Date) Time in milliseconds since unix Epoch. Default: The current time is used.
  • nsecs - (Number between 0-9999) additional time, in 100-nanosecond units. Ignored if msecs is unspecified. Default: internal uuid counter is used, as per 4.2.1.2.

• buffer - (Array | Buffer) Array or buffer where UUID bytes are to be written.

• offset - (Number) Starting index in buffer at which to begin writing.

Returns buffer, if specified, otherwise the string form of the UUID

Note: The id is generated guaranteed to stay constant for the lifetime of the current JS runtime. (Future versions of this module may use persistent storage mechanisms to extend this guarantee.)

Example: Generate string UUID with fully-specified options

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

Example: In-place generation of two binary IDs

// Generate two ids in an array
const arr = new Array(32); // -> []
uuidv1(null, arr, 0);   // -> [02 a2 ce 90 14 32 11 e1 85 58 0b 48 8e 4f c1 15]
uuidv1(null, arr, 16);  // -> [02 a2 ce 90 14 32 11 e1 85 58 0b 48 8e 4f c1 15 02 a3 1c b0 14 32 11 e1 85 58 0b 48 8e 4f c1 15]

const uuidv4 = require('uuid/v4')

// Allowed arguments
uuidv4();
uuidv4(options);
uuidv4(options, buffer, offset);

Generate and return a RFC4122 v4 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
  • rng - (Function) Random # generator function that returns an Array[16] of byte values (0-255)
• buffer - (Array | Buffer) Array or buffer where UUID bytes are to be written.
• offset - (Number) Starting index in buffer at which to begin writing.

Returns buffer, if specified, otherwise the string form of the UUID

Example: Generate string UUID with fully-specified options

uuid.v4({
  random: [
    0x10, 0x91, 0x56, 0xbe, 0xc4, 0xfb, 0xc1, 0xea,
    0x71, 0xb4, 0xef, 0xe1, 0x67, 0x1c, 0x58, 0x36
  ]
});
// -> "109156be-c4fb-41ea-b1b4-efe1671c5836"

Example: Generate two IDs in a single buffer

const buffer = new Array(32); // (or 'new Buffer' in node.js)
uuid.v4(null, buffer, 0);
uuid.v4(null, buffer, 16);

const uuidv5 = require('uuid/v4');

// Allowed arguments
uuidv5(name, namespace);
uuidv5(name, namespace, buffer);
uuidv5(name, namespace, buffer, offset);

Generate and return a RFC4122 v4 UUID.

• name - (String | Array[]) "name" to create UUID with
• namespace - (String | Array[]) "namespace" UUID either as a String or Array[16] of byte values
• buffer - (Array | Buffer) Array or buffer where UUID bytes are to be written.
• offset - (Number) Starting index in buffer at which to begin writing. Default = 0

Returns buffer, if specified, otherwise the string form of the UUID

Example:

// Generate a unique  namespace (typically you would do this once, outside of
// your project, then bake this value into your code)
const uuidv4 = require('uuid/v4');
const MY_NAMESPACE = uuidv4();  //

// Generate a couple namespace uuids
const uuidv5 = require('uuid/v5');
uuidv5('hello', MY_NAMESPACE);
uuidv5('world', MY_NAMESPACE);

npm test

The API below is available for legacy purposes and is not expected to be available post-3.X

const uuid = require('uuid');

uuid.v1(...); // alias of uuid/v1
uuid.v4(...); // alias of uuid/v4
uuid(...);    // alias of uuid/v4

// uuid.v5() is not supported in this API

The code for the legacy node-uuid package is available in the node-uuid branch.