Web3 Framework, 0% Backend, 10000% Frontend

// blockend.js
import { Feed, Modem56, PicoStore, Hub } from 'picostack'
import levelup from 'levelup'
import leveljs from 'level-js'

// Set up user identity
const { sk } = Feed.signPair()
const userFeed = new Feed()

// Set up the app state handler / store
const DB = levelup(leveljs('myapp')) // Open IndexedDB
const store = new PicoStore(DB)
store.register(TimeReducer())
await store.load() // Restores previously saved state

// Setup a minimal network-controller
const hub = new Hub(async (node, message, reply) => {
  if (message === 'Hello') {
    // Send local blocks
    await reply(userFeed.pickle())
  } else {
    // Accept remote blocks
    const blocks = Feed.from(message)
    await store.dispatch(blocks)
  }
})

// Connect to swarm
const modem = new Modem56()
modem.join('A topic', peer => hub.createWire(wire => {
  console.info('Peer connected', peer)
  wire.postMessage('Hello')
    .catch(console.error)
}))

async function mutate (payload) {
  userFeed.append(JSON.stringify(payload), sk)
  const accepted = await store.dispatch(userFeed, true)
  // TODO: hub.broadcast(accepted)
}

// PicoStore is a virtual-computer that runs blocks as
// if they are lines of code.
// Accepted blocks modify the computer's internal state.
// The reducers acts as the 'brains'
// deciding which instructions to run.
// A.k.a. 'The Consensus'.
// Please don't PoW or I'll get really upset.
function TimeReducer () {
  return {
    name: 'DecentTime',
    filter ({ block, state }) {
      const v = JSON.parse(block.body)
      // Reject invalid blocks
      if (v > Date.now()) return 'Invalid block from the future'
      if (v < state) return 'Outdated block'

      // Accept valid blocks
      return false
    },
    reducer ({ block }) => {
      // Mutate state
      return JSON.parse(block.body)
    }
  }
}
export { store, mutate }