# 
[](https://www.npmjs.com/package/@thi.ng/bitfield)
[](https://mastodon.thi.ng/@toxi)
> [!NOTE]
> This is one of 214 standalone projects, maintained as part
> of the [@thi.ng/umbrella](https://codeberg.org/thi.ng/umbrella/) ecosystem
> and anti-framework.
>
> 🚀 Please help me to work full-time on these projects by [sponsoring
> me](https://codeberg.org/thi.ng/umbrella/src/branch/develop/CONTRIBUTING.md#donations).
> Thank you! ❤️
- [About](#about)
- [Status](#status)
- [Related packages](#related-packages)
- [Installation](#installation)
- [Dependencies](#dependencies)
- [Usage examples](#usage-examples)
- [API](#api)
- [Authors](#authors)
- [License](#license)
## About
1D / 2D bit field implementations.
All implementations are backed by typed arrays. Due to `Uint32Array`
backing the width is always rounded to a multiple of 32.
## Status
**STABLE** - used in production
[Search or submit any issues for this package](https://codeberg.org/thi.ng/umbrella/issues?q=%5Bbitfield%5D)
## Related packages
- [@thi.ng/adjacency](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/adjacency) - Sparse & bitwise adjacency matrices, lists and selected traversal algorithms for directed & undirected graphs
## Installation
```bash
yarn add @thi.ng/bitfield
```
ESM import:
```ts
import * as bf from "@thi.ng/bitfield";
```
Browser ESM import:
```html
```
[JSDelivr documentation](https://www.jsdelivr.com/)
For Node.js REPL:
```js
const bf = await import("@thi.ng/bitfield");
```
Package sizes (brotli'd, pre-treeshake): ESM: 1.61 KB
## Dependencies
- [@thi.ng/api](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/api)
- [@thi.ng/binary](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/binary)
- [@thi.ng/errors](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/errors)
- [@thi.ng/strings](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/strings)
Note: @thi.ng/api is in _most_ cases a type-only import (not used at runtime)
## Usage examples
One project in this repo's
[/examples](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples)
directory is using this package:
| Screenshot | Description | Live demo | Source |
|:----------------------------------------------------------------------------------------------------------------------|:-------------------------------------------------------------------|:-----------------------------------------------------|:------------------------------------------------------------------------------------------|
| 
| Responsive image gallery with tag-based Jaccard similarity ranking | [Demo](https://demo.thi.ng/umbrella/related-images/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/related-images) |
## API
[Generated API docs](https://docs.thi.ng/umbrella/bitfield/)
```ts
import { BitField, BitMatrix } from "@thi.ng/bitfield";
// size always rounded up to a multiple of 32
const field = new BitField(16);
field.setAt(0);
// if 2nd arg is false, the bit will be cleared
// setAt returns non-zero value if bit was previously set
field.setAt(31, true);
// 0
// returns non-zero value if bit is set
field.at(0)
// -2147483648
field.at(1)
// 0
field.toString();
// 10000000000000000000000000000001
field.resize(64)
// 1000000000000000000000000000000100000000000000000000000000000000
const mat = new BitMatrix(8, 32);
for(let i = 0; i < 8; i++) mat.setAt(i, i);
mat.at(7, 7);
// 16777216
mat.toString();
// 10000000000000000000000000000000
// 01000000000000000000000000000000
// 00100000000000000000000000000000
// 00010000000000000000000000000000
// 00001000000000000000000000000000
// 00000100000000000000000000000000
// 00000010000000000000000000000000
// 00000001000000000000000000000000
```
## Authors
- [Karsten Schmidt](https://thi.ng)
If this project contributes to an academic publication, please cite it as:
```bibtex
@misc{thing-bitfield,
title = "@thi.ng/bitfield",
author = "Karsten Schmidt",
note = "https://thi.ng/bitfield",
year = 2016
}
```
## License
© 2016 - 2026 Karsten Schmidt // Apache License 2.0