extracted from the interface-ipfs-core

index.js

'use strict'

// var IPFS = require('ipfs-api')
var IPFS = require('../../src/')

var ipfs = IPFS()

function store () {
  var toStore = document.getElementById('source').value
  ipfs.files.add(Buffer.from(toStore), function (err, res) {
    if (err || !res) {
      return console.error('ipfs add error', err, res)
    }

    res.forEach(function (file) {
      if (file && file.hash) {
        console.log('successfully stored', file.hash)
        display(file.hash)
      }
    })
  })
}

function display (hash) {
  // buffer: true results in the returned result being a buffer rather than a stream
  ipfs.files.cat(hash, function (err, res) {
    if (err || !res) {
      return console.error('ipfs cat error', err, res)
    }

    document.getElementById('hash').innerText = hash
    document.getElementById('content').innerText = res.toString()
  })
}

function pubsub_list () {
  ipfs.pubsub.ls((err, response) => {console.log(err); console.log(response)})
}

function pubsub_sub () {
  console.log('in pubsub_sub')
  ipfs.pubsub.subscribe('shunkintestpubsub', messageHandler, (message) => {
    console.log('subscribed!')
  })
}

function pubsub_unsub () {
  console.log('in pubsub_unsub')
  ipfs.pubsub.unsubscribe('shunkintestpubsub', messageHandler, (err) => {
    if (err) {
      return console.error(`failed to unsubscribe from topic`, err)
    }
    console.log(`unsubscribed from topic`)
  })
}

function messageHandler (message) {
  console.log('got message from ' + message.from)
  // data is a buffer. Here we're converting it into a string
  const data = message.data.toString()
  console.log('containing data: ' + data)
}

function makeCheck (n, done) {
  let i = 0
  return (err) => {
    if (err) {
      // return done(err)
      console.log(err + "HAPPEND")
    }

    if (++i === n) {
      // done()
      console.log("Second call : success")
    } else {
      console.log("First call")    
    }
  }
}

function test_function () {
  // const sampleCheck = makeCheck(2, done)
  const sampleCheck = makeCheck(2)
  let topic = "shunkintesttest"
  const handler = (msg) => {
    console.log("handler is here")
    ipfs.pubsub.unsubscribe(topic, handler, (err) => {
      ipfs.pubsub.ls((err, topics) => {
        console.log(topics)
        sampleCheck()
      })
    })
  }

  ipfs.pubsub.subscribe(topic, handler, (err) => {
    ipfs.pubsub.publish(topic, Buffer.from('hi'), sampleCheck)
  })
}

document.addEventListener('DOMContentLoaded', function () {
  document.getElementById('store').onclick = store
  document.getElementById('list').onclick = pubsub_list
  document.getElementById('sub').onclick = pubsub_sub
  document.getElementById('unsub').onclick = pubsub_unsub
  document.getElementById('test').onclick = test_function 
})

ipfs.pubsub.subscribe('shunkintestpubsub', messageHandler)

const data = Buffer.from('some message content here')

ipfs.pubsub.publish('shunkintestpubsub', data, (err) => {
  if (err) {
    console.error('error publishing: ', err)
  } else {
    console.log('successfully published message')
  }
})

ipfs.pubsub.ls((err, response) => {console.log(err); console.log(response)})