# node-uuid

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

Features:

* Generate RFC4122 version 1 or version 4 UUIDs
* Runs in node.js and all browsers.
* Cryptographically strong random # generation on supporting platforms
* 1.1K minified and gzip'ed

## Getting Started

Install it in your browser:

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

Or in node.js:

```
npm install node-uuid
```

```javascript
var uuid = require('node-uuid');
```

Then create some ids ...

```javascript
// 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: Randomnly generated ID.  See note 2.
  * `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.  See note 3.
  * `nsecs` - (Number between 0-9999) additional time, in 100-nanosecond. 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:

1. 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.)
1. Specifying the `msecs` option bypasses the internal logic for ensuring id uniqueness.  In this case you may want to also provide `clockseq` and `nsecs` options as well.

Example: Generate string UUID with fully-specified options

```javascript
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

```javascript
// In browsers: 'new Array(32)'
var buffer = new Buffer(32).fill(0);  // -> <Buffer 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00>
uuid.v1(null, buffer, 0);             // -> <Buffer 02 a2 ce 90 14 32 11 e1 85 58 0b 48 8e 4f c1 15 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00>
uuid.v1(null, buffer, 16);            // -> <Buffer 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

* `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

```javascript
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

```javascript
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

```javascript
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 node-uuid object.

Example:

```javascript
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 uuid.js
```

In Browser

```
open test/test.html
```

### Benchmarking

Requires node.js

```
npm install uuid uuid-js
node test/benchmark.js
```

For a more complete discussion of node-uuid performance, please see the `benchmark/README.md` file, and the [benchmark wiki](https://github.com/broofa/node-uuid/wiki/Benchmark)

For browser performance [checkout the JSPerf tests](http://jsperf.com/node-uuid-performance).

### Release notes

v1.3: Includes

* Support for version 1 ids, thanks to [@ctavan](https://github.com/ctavan)!
* Support for node.js crypto API
* De-emphasizing performance in favor of a) cryptographic quality PRNGs where available and b) more manageable code