> For the complete documentation index, see [llms.txt](https://curby.gitbook.io/rand-utils/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://curby.gitbook.io/rand-utils/readme.md).

# README

**@buff-beacon-project/rand-utils v1.0.0** • **Docs**

***

## @buff-beacon-project/rand-utils v1.0.0

## Rand Utils

rand-utils is a collection of utilities for working with pre-generated random bits. This is useful for working with public randomness beacon data or any other sources of random bits.

All methods in this library are deterministic and based on the input bits.

### Installation

```bash
npm install @buff-beacon-project/rand-utils
```

### Example

```ts
import { BitReader } from '@buff-beacon-project/rand-utils'
import { randomBytes } from 'crypto'

// create some random bits
const rand = randomBytes(64)
// create a bit reader
const reader = BitReader.from(rand)

// random directions
const directions = ['up', 'down', 'left', 'right']
const randomDirections = reader.unfold((stream) =>
  directions[stream.readBits(2, false)]
)
const list = Array.from(randomDirections)
// => [ 'down', 'right', 'up', 'left', 'down', 'right', 'up', 'left', ... ]

// shuffle an array
const arr = [0, 1, 2, 3, 4, 5, 6, 7]
const shuffled = reader.shuffled(arr)
// => [ 3, 0, 7, 4, 1, 6, 2, 5 ]
```

### Classes

| Class                                         | Description                                    |
| --------------------------------------------- | ---------------------------------------------- |
| [BitReader](/rand-utils/classes/bitreader.md) | Helper class to read bits from an ArrayBuffer. |

### Functions

| Function                                                    | Description                                                                                                      |
| ----------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- |
| [boundedRandom](/rand-utils/functions/boundedrandom.md)     | Get an unbiased "random" number within the range `[0, s)` from a bitStream.                                      |
| [getShuffleSeed](/rand-utils/functions/getshuffleseed.md)   | Return an array fully filled with bounded random values appropriate to shuffle a list.                           |
| [shuffle](/rand-utils/functions/shuffle.md)                 | Get a shuffled copy of provided array using the given shuffle seed.                                              |
| [shuffleSelf](/rand-utils/functions/shuffleself.md)         | Shuffle provided array **in place** using the given shuffle seed.                                                |
| [unfoldBitstream](/rand-utils/functions/unfoldbitstream.md) | Utility to yield results from provided function using a bitstream. Stops when bitstream runs out of usable bits. |