JavaScript generate ENS contenthash (content) IPFS IPNS hash value

contenthash.js

const bs58 = require('bs58')
const contentHash = require('content-hash')

const domain = 'app.uniswap.org'
const text = `ipns://${domain}`
const matched = text.match(/^(ipfs|ipns|bzz|onion|onion3):\/\/(.*)/) || text.match(/\/(ipfs)\/(.*)/) || text.match(/\/(ipns)\/(.*)/)
const contentType = matched[1]
const content = matched[2]

const bs58content = bs58.encode(
  Buffer.concat([
    Buffer.from([0, content.length]),
    Buffer.from(content)
  ])
)

const ensContentHash = '0x' + contentHash.encode('ipns-ns', bs58content)
console.log(ensContentHash) // 0xe5010170000f6170702e756e69737761702e6f7267

const decoded = contentHash.decode(ensContentHash)
console.log(decoded) // 12uA8M8Ku8mHUumxHcu7uee