@ipld/dag-json

JSON Directed Acrylic Graph for IPLD

You probably don't want to use this library directly and instead access it through the Block interface.

Usage (w/ Block Interface):

import multiformats from 'multiformats/basics'
import { create } from '@ipld/block'
multiformats.add(require('@ipld/dag-json'))
const Block = create(multiformats)
const { CID } = Block

const obj = {
  x: 1,
  /* CID instances are encoded as links */
  y: [2, 3, CID.from('QmaozNR7DZHQK1ZcU9p7QdrshMvXqWK6gpu5rmrkPdT3L4')],
  z: {
    a: CID.from('QmaozNR7DZHQK1ZcU9p7QdrshMvXqWK6gpu5rmrkPdT3L4'),
    b: null,
    c: 'string'
  }
}

let encoder = Block.encoder(obj, 'dag-json')
let encoded = await Block.encode() // binary encoded block
let decoded = await Block.decoder(encoded, 'dag-json').decode()
decoded.y[0] // 2
CID.asCID(decoded.z.a) // cid instance

Spec

The dag-json spec is quite simple.

Nodes are in standard JSON format with the following requirements:

• Objects are consistent and deterministic
  • Object keys are sorted (TODO: specify sorting algorithm).
  • No whitespace outside of values. {"x":1,"y":[2,3]}
• Links are encoded as objects with a single '/' value of the base58 encoded CID.
  • {"/": "QmaozNR7DZHQK1ZcU9p7QdrshMvXqWK6gpu5rmrkPdT3L4"}

That's all :)