https://github.com/ipld/js-dag-cbor

dag-cbor codec for IPLD
https://github.com/ipld/js-dag-cbor

Last synced: about 13 hours ago
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dag-cbor codec for IPLD

• Host: GitHub
• URL: https://github.com/ipld/js-dag-cbor
• Owner: ipld
• License: other
• Created: 2020-05-12T04:17:12.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2024-10-29T23:05:41.000Z (about 2 months ago)
• Last Synced: 2024-11-30T17:28:22.412Z (14 days ago)
• Language: JavaScript
• Homepage:
• Size: 299 KB
• Stars: 27
• Watchers: 19
• Forks: 17
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# @ipld/dag-cbor 

[![codecov](https://img.shields.io/codecov/c/github/ipld/js-dag-cbor.svg?style=flat-square)](https://codecov.io/gh/ipld/js-dag-cbor)

[![CI](https://img.shields.io/github/workflow/status/ipld/js-dag-cbor/test%20&%20maybe%20release/master?style=flat-square)](https://github.com/ipld/js-dag-cbor/actions/workflows/js-test-and-release.yml)

> JS implementation of DAG-CBOR

## Table of contents 

- [Install](#install)

- [Spec](#spec)

- [License](#license)

- [Contribute](#contribute)

## Install

```console

$ npm i @ipld/dag-cbor

```

This is the *new* interface meant for use by itself or with `multiformats` and

`@ipld/block`. It is not used by `js-ipld-format` which is currently

used in IPFS. That library is [here](https://github.com/ipld/js-ipld-dag-cbor).

Usage:

```javascript

import { encode, decode } from '@ipld/dag-cbor'

import { CID } from 'multiformats'

const obj = {

  x: 1,

  /* CID instances are encoded as links */

  y: [2, 3, CID.parse('QmaozNR7DZHQK1ZcU9p7QdrshMvXqWK6gpu5rmrkPdT3L4')],

  z: {

    a: CID.parse('QmaozNR7DZHQK1ZcU9p7QdrshMvXqWK6gpu5rmrkPdT3L4'),

    b: null,

    c: 'string'

  }

}

let data = encode(obj)

let decoded = decode(data)

decoded.y[0] // 2

CID.asCID(decoded.z.a) // cid instance

// encode/decode options are exported for use with cborg's encodedLength and decodeFirst

import { encodeOptions, decodeOptions } from '@ipld/dag-cbor'

import { encodedLength } from 'cborg/length'

import { decodeFirst } from 'cborg'

// dag-cbor encoded length of obj in bytes

const byteLength = encodedLength(obj, encodeOptions)

byteLength // 104

// concatenate two dag-cbor encoded obj

const concatenatedData = new Uint8Array(data.length * 2)

concatenatedData.set(data)

concatenatedData.set(data, data.length)

// returns dag-cbor decoded obj at the beginning of the buffer as well as the remaining bytes

const [first, remainder] = decodeFirst(concatenatedData, decodeOptions)

assert.deepStrictEqual(first, obj)

assert.deepStrictEqual(remainder, data)

```

## Spec

The [`dag-cbor` specification is in the IPLD specs repo](https://github.com/ipld/specs/blob/master/block-layer/codecs/dag-cbor.md).

## License

Licensed under either of

- Apache 2.0, ([LICENSE-APACHE](LICENSE-APACHE) / )

- MIT ([LICENSE-MIT](LICENSE-MIT) / )

## Contribute

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.