# uuid [](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(); // ⇨ '45745c60-7b1a-11e8-9c9c-2d42b21b1a3e'
```
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(); // ⇨ '10ba038e-48da-487b-96e8-8d3b99b6d18a'
```
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
```
For version 3 uuids:
```html
```
For version 4 uuids:
```html
```
For version 5 uuids:
```html
```
## 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 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); // ⇨ [ 69, 117, 109, 208, 123, 26, 17, 232, 146, 52, 45, 66, 178, 27, 26, 62 ]
uuidv1(null, arr, 16); // ⇨ [ 69, 117, 109, 208, 123, 26, 17, 232, 146, 52, 45, 66, 178, 27, 26, 62, 69, 117, 109, 209, 123, 26, 17, 232, 146, 52, 45, 66, 178, 27, 26, 62 ]
```
### 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); // ⇨ [ 54, 122, 218, 70, 45, 70, 65, 24, 171, 53, 95, 130, 83, 195, 242, 45 ]
uuidv4(null, buffer, 16); // ⇨ [ 54, 122, 218, 70, 45, 70, 65, 24, 171, 53, 95, 130, 83, 195, 242, 45, 108, 204, 255, 103, 171, 86, 76, 94, 178, 225, 188, 236, 150, 20, 151, 87 ]
```
### 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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