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```javascript --hide
runmd.onRequire = path => path.replace(/^uuid/, './');
```
# 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 --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](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 --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
```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 --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
```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 --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
```shell
npm test
```