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uuid

Simple, fast generation of RFC4122 UUIDS.

Features:

Generate RFC4122 version 1 or version 4 UUIDs
Runs in node.js and all browsers.
Cryptographically strong random # generation on supporting platforms
1185 bytes minified and gzip'ed (Want something smaller? Check this crazy shit out! )
Annotated source code

Getting Started

Install it in your browser:

<script src="uuid.js"></script>

Or in node.js:

npm install uuid

var uuid = require('uuid');

// Generate a v1 (time-based) id
uuid.v1(); // -> '6c84fb90-12c4-11e1-840d-7b25c5ee775a'

// Generate a v4 (random) id
uuid.v4(); // -> '110ec58a-a0f2-4ac4-8393-c866d813b8d1'

API

uuid.v1([`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

Notes:

The randomly generated node id is only 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

uuid.v1({
  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
var arr = new Array(32); // -> []
uuid.v1(null, arr, 0);   // -> [02 a2 ce 90 14 32 11 e1 85 58 0b 48 8e 4f c1 15]
uuid.v1(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]

// Optionally use uuid.unparse() to get stringify the ids
uuid.unparse(buffer);    // -> '02a2ce90-1432-11e1-8558-0b488e4fc115'
uuid.unparse(buffer, 16) // -> '02a31cb0-1432-11e1-8558-0b488e4fc115'

uuid.v4([`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 to use. Set to one of the built-in generators - uuid.mathRNG (all platforms), uuid.nodeRNG (node.js only), uuid.whatwgRNG (WebKit only) - or a custom function that returns an 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.

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

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

uuid.parse(id[, buffer[, offset]])

uuid.unparse(buffer[, offset])

Parse and unparse UUIDs

id - (String) UUID(-like) string
buffer - (Array | Buffer) Array or buffer where UUID bytes are to be written. Default: A new Array or Buffer is used
offset - (Number) Starting index in buffer at which to begin writing. Default: 0

Example parsing and unparsing a UUID string

var bytes = uuid.parse('797ff043-11eb-11e1-80d6-510998755d10'); // -> <Buffer 79 7f f0 43 11 eb 11 e1 80 d6 51 09 98 75 5d 10>
var string = uuid.unparse(bytes); // -> '797ff043-11eb-11e1-80d6-510998755d10'

uuid.noConflict()

(Browsers only) Set uuid property back to it's previous value.

Returns the uuid object.

Example:

var myUuid = uuid.noConflict();
myUuid.v1(); // -> '6c84fb90-12c4-11e1-840d-7b25c5ee775a'

Deprecated APIs

Support for the following v1.2 APIs is available in v1.3, but is deprecated and will be removed in the next major version.

uuid([format [, buffer [, offset]]])

uuid() has become uuid.v4(), and the format argument is now implicit in the buffer argument. (i.e. if you specify a buffer, the format is assumed to be binary).

uuid.BufferClass

The class of container created when generating binary uuid data if no buffer argument is specified. This is expected to go away, with no replacement API.

Testing

In node.js

> cd test
> node test.js

In Browser

open test/test.html

Benchmarking

Requires node.js

cd benchmark/
npm install
node benchmark.js

For a more complete discussion of uuid performance, please see the benchmark/README.md file, and the benchmark wiki

For browser performance checkout the JSPerf tests.

Release notes

1.4.0

Improved module context detection
Removed public RNG functions

1.3.2

Improve tests and handling of v1() options (Issue #24)
Expose RNG option to allow for perf testing with different generators

1.3.0

Support for version 1 ids, thanks to @ctavan!
Support for node.js crypto API
De-emphasizing performance in favor of a) cryptographic quality PRNGs where available and b) more manageable code

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