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```javascript --hide
runmd.onRequire = path => path.replace(/^uuid/, './');


# 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 --run v1
const uuidv1 = require('uuid/v1');
uuidv1(); // RESULT


Version 3 (namespace):

```javascript --run v3
const uuidv3 = require('uuid/v3');

// ... using predefined DNS namespace (for domain names)
uuidv3('hello.example.com', uuidv3.DNS); // RESULT

// ... using predefined URL namespace (for, well, URLs)
uuidv3('http://example.com/hello', uuidv3.URL); // RESULT

// ... 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); // RESULT


Version 4 (random):

```javascript --run v4
const uuidv4 = require('uuid/v4');
uuidv4(); // RESULT


Version 5 (namespace):

```javascript --run v5
const uuidv5 = require('uuid/v5');

// ... using predefined DNS namespace (for domain names)
uuidv5('hello.example.com', uuidv5.DNS); // RESULT

// ... using predefined URL namespace (for, well, URLs)
uuidv5('http://example.com/hello', uuidv5.URL); // RESULT

// ... 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); // RESULT


Quickstart - Browser-ready Versions

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 3 uuids:

<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:

<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>


API


Version 1

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  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 --run v1
const v1options = {
  node: [0x01, 0x23, 0x45, 0x67, 0x89, 0xab],
  clockseq: 0x1234,
  msecs: new Date('2011-11-01').getTime(),
  nsecs: 5678
};
uuidv1(v1options); // RESULT


Example: In-place generation of two binary IDs

```javascript --run v1
// Generate two ids in an array
const arr = new Array();
uuidv1(null, arr, 0);  // RESULT
uuidv1(null, arr, 16); // RESULT


Version 3

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 --run v3
uuidv3('hello world', MY_NAMESPACE);  // RESULT


### 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 --run v4
const v4options = {
  random: [
    0x10, 0x91, 0x56, 0xbe, 0xc4, 0xfb, 0xc1, 0xea,
    0x71, 0xb4, 0xef, 0xe1, 0x67, 0x1c, 0x58, 0x36
  ]
};
uuidv4(v4options); // RESULT


Example: Generate two IDs in a single buffer

```javascript --run v4
const buffer = new Array();
uuidv4(null, buffer, 0);  // RESULT
uuidv4(null, buffer, 16); // RESULT


Version 5

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 --run v5
uuidv5('hello world', MY_NAMESPACE);  // RESULT


## 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

npm test