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# uuid [![Build Status](https://secure.travis-ci.org/kelektiv/node-uuid.svg?branch=master)](http://travis-ci.org/kelektiv/node-uuid) #

Simple, fast generation of [RFC4122](http://www.ietf.org/rfc/rfc4122.txt) UUIDS.

Features:

* Support for version 1, 3, 4 and 5 UUIDs

* Cross-platform

* Uses cryptographically-strong random number APIs (when available)

* Zero-dependency, small footprint (... but not [this small](https://gist.github.com/982883))

[**Deprecation warning**: The use of `require('uuid')` is deprecated and will not be

supported after version 3.x of this module.  Instead, use `require('uuid/[v1|v3|v4|v5]')` as shown in the examples below.]

## Quickstart - CommonJS (Recommended)

```shell

npm install uuid

```

Then generate your uuid version of choice ...

Version 1 (timestamp):

```javascript

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

uuidv1(); // ⇨ 'f64f2940-fae4-11e7-8c5f-ef356f279131'

```

Version 3 (namespace):

```javascript

const uuidv3 = require('uuid/v3');

// ... using predefined DNS namespace (for domain names)

uuidv3('hello.example.com', uuidv3.DNS); // ⇨ '9125a8dc-52ee-365b-a5aa-81b0b3681cf6'

// ... using predefined URL namespace (for, well, URLs)

uuidv3('http://example.com/hello', uuidv3.URL); // ⇨ 'c6235813-3ba4-3801-ae84-e0a6ebb7d138'

// ... using a custom namespace

//

// Note: Custom namespaces should be a UUID string specific to your application!

// E.g. the one here was generated using this modules `uuid` CLI.

const MY_NAMESPACE = '1b671a64-40d5-491e-99b0-da01ff1f3341';

uuidv3('Hello, World!', MY_NAMESPACE); // ⇨ 'e8b5a51d-11c8-3310-a6ab-367563f20686'

```

Version 4 (random):

```javascript

const uuidv4 = require('uuid/v4');

uuidv4(); // ⇨ '416ac246-e7ac-49ff-93b4-f7e94d997e6b'

```

Version 5 (namespace):

```javascript

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

//

// Note: Custom namespaces should be a UUID string specific to your application!

// E.g. the one here was generated using this modules `uuid` CLI.

const MY_NAMESPACE = '1b671a64-40d5-491e-99b0-da01ff1f3341';

uuidv5('Hello, World!', MY_NAMESPACE); // ⇨ '630eb68f-e0fa-5ecc-887a-7c7a62614681'

```

## Quickstart - Browser-ready Versions

Browser-ready versions of this module are available via [wzrd.in](https://github.com/jfhbrook/wzrd.in).

For version 1 uuids:

```html

<script src="http://wzrd.in/standalone/uuid%2Fv1@latest"></script>

<script>

uuidv1(); // -> v1 UUID

</script>

```

For version 3 uuids:

```html

<script src="http://wzrd.in/standalone/uuid%2Fv3@latest"></script>

<script>

uuidv3('http://example.com/hello', uuidv3.URL); // -> v3 UUID

</script>

```

For version 4 uuids:

```html

<script src="http://wzrd.in/standalone/uuid%2Fv4@latest"></script>

<script>

uuidv4(); // -> v4 UUID

</script>

```

For version 5 uuids:

```html

<script src="http://wzrd.in/standalone/uuid%2Fv5@latest"></script>

<script>

uuidv5('http://example.com/hello', uuidv5.URL); // -> v5 UUID

</script>

```

## API

### Version 1

```javascript

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

// Incantations

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) 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 <node> 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

```javascript

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

```javascript

// Generate two ids in an array

const arr = new Array();

uuidv1(null, arr, 0);  // ⇨ [ 246, 87, 141, 176, 250, 228, 17, 231, 146, 52, 239, 53, 111, 39, 145, 49 ]

uuidv1(null, arr, 16); // ⇨ [ 246, 87, 141, 176, 250, 228, 17, 231, 146, 52, 239, 53, 111, 39, 145, 49, 246, 87, 180, 192, 250, 228, 17, 231, 146, 52, 239, 53, 111, 39, 145, 49 ]

```

### Version 3

```javascript

const uuidv3 = require('uuid/v3');

// Incantations

uuidv3(name, namespace);

uuidv3(name, namespace, buffer);

uuidv3(name, namespace, buffer, offset);

```

Generate and return a RFC4122 v3 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:

```javascript

uuidv3('hello world', MY_NAMESPACE);  // ⇨ '042ffd34-d989-321c-ad06-f60826172424'

```

### Version 4

```javascript

const uuidv4 = require('uuid/v4')

// Incantations

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 predefined `random` values

```javascript

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

```javascript

const buffer = new Array();

uuidv4(null, buffer, 0);  // ⇨ [ 175, 10, 162, 184, 217, 255, 77, 139, 161, 80, 41, 200, 70, 238, 196, 250 ]

uuidv4(null, buffer, 16); // ⇨ [ 175, 10, 162, 184, 217, 255, 77, 139, 161, 80, 41, 200, 70, 238, 196, 250, 75, 162, 105, 153, 48, 238, 77, 58, 169, 56, 158, 207, 106, 160, 47, 239 ]

```

### Version 5

```javascript

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

// Incantations

uuidv5(name, namespace);

uuidv5(name, namespace, buffer);

uuidv5(name, namespace, buffer, offset);

```

Generate and return a RFC4122 v5 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:

```javascript

uuidv5('hello world', MY_NAMESPACE);  // ⇨ '9f282611-e0fd-5650-8953-89c8e342da0b'

```

## Command Line

UUIDs can be generated from the command line with the `uuid` command.

```shell

$ uuid

ddeb27fb-d9a0-4624-be4d-4615062daed4

$ uuid v1

02d37060-d446-11e7-a9fa-7bdae751ebe1

```

Type `uuid --help` for usage details

## Testing

```shell

npm test

```

----

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