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@ipld/dag-cbor <!-- omit in toc -->

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JS implementation of DAG-CBOR

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Install

$ 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.

Usage:

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.

License

Licensed under either of

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.