Walk through all addresses derived from a mnemonic and sum up balances

mnemonic-balance.js

const got = require('got')
const Mnemonic = require('bitcore-mnemonic')

const mnemonic = '? ? ? ? ? ? ? ? ? ? ? ?' // 12-word mnemonic
const words = Mnemonic.Words.ENGLISH // or SPANISH, etc
const derivationPath = "m/44'/0'/0'" // BIP-44

const insightApiUrl = 'https://insight.bitpay.com/api'

const toBtc = sat => sat / 100000000

const hdPrivKey = new Mnemonic(mnemonic, words).toHDPrivateKey()

let balance = 0

function printBalance (addr) {
  return got(`${insightApiUrl}/addr/${addr}/balance`, { json: true})
    .then(function (res) {
      console.log(`${addr}: ${toBtc(res.body)}`)
      balance += res.body
    })
}

function getBalance (accountKey, index) {
  const privateKey = accountKey.derive(0).derive(index).privateKey
  const addr = privateKey.toAddress().toString()
  return addr && got(`${insightApiUrl}/txs?address=${addr}`, { json: true})
    .then(res => res.body.txs.length && printBalance(addr).then(() => true))
}

function promiseLoop (fn) {
  const loop = i => Promise.resolve(fn(i)).then(cont => cont ? loop(i + 1) : i)  
  return loop(0)
}

promiseLoop(i => getBalance(hdPrivKey.derive(derivationPath), i))
  .then(function () {
    console.log(`Total: ${toBtc(balance)}`)
  })