How to use the web3.toBN function in web3

const { checkHTTPS, watchdog } = require('./utils/utils')
const { EXIT_CODES } = require('./utils/constants')

if (process.argv.length < 3) {
  logger.error('Please check the number of arguments, config file was not provided')
  process.exit(EXIT_CODES.GENERAL_ERROR)
}

const config = require(path.join('../config/', process.argv[2]))

const processSignatureRequests = require('./events/processSignatureRequests')(config)
const processCollectedSignatures = require('./events/processCollectedSignatures')(config)
const processAffirmationRequests = require('./events/processAffirmationRequests')(config)
const processTransfers = require('./events/processTransfers')(config)

const ZERO = toBN(0)
const ONE = toBN(1)

const web3Instance = config.web3
const bridgeContract = new web3Instance.eth.Contract(config.bridgeAbi, config.bridgeContractAddress)
const eventContract = new web3Instance.eth.Contract(config.eventAbi, config.eventContractAddress)
const lastBlockRedisKey = `${config.id}:lastProcessedBlock`
let lastProcessedBlock = BN.max(config.startBlock.sub(ONE), ZERO)

async function initialize() {
  try {
    const checkHttps = checkHTTPS(process.env.ALLOW_HTTP, logger)

    rpcUrlsManager.homeUrls.forEach(checkHttps('home'))
    rpcUrlsManager.foreignUrls.forEach(checkHttps('foreign'))

    await getLastProcessedBlock()

const config = require(path.join('../config/', process.argv[2]))

const processSignatureRequests = require('./events/processSignatureRequests')(config)
const processCollectedSignatures = require('./events/processCollectedSignatures')(config)
const processAffirmationRequests = require('./events/processAffirmationRequests')(config)
const processTransfers = require('./events/processTransfers')(config)
const processHalfDuplexTransfers = require('./events/processHalfDuplexTransfers')(config)
const processAMBSignatureRequests = require('./events/processAMBSignatureRequests')(config)
const processAMBCollectedSignatures = require('./events/processAMBCollectedSignatures')(config)
const processAMBAffirmationRequests = require('./events/processAMBAffirmationRequests')(config)

const { getTokensState } = require('./utils/tokenState')

const ZERO = toBN(0)
const ONE = toBN(1)

const web3Instance = config.web3
const bridgeContract = new web3Instance.eth.Contract(config.bridgeAbi, config.bridgeContractAddress)
let { eventContractAddress } = config
let eventContract = new web3Instance.eth.Contract(config.eventAbi, eventContractAddress)
let skipEvents = config.idle
const lastBlockRedisKey = `${config.id}:lastProcessedBlock`
let lastProcessedBlock = BN.max(config.startBlock.sub(ONE), ZERO)

async function initialize() {
  try {
    const checkHttps = checkHTTPS(process.env.ORACLE_ALLOW_HTTP_FOR_RPC, logger)

    rpcUrlsManager.homeUrls.forEach(checkHttps('home'))
    rpcUrlsManager.foreignUrls.forEach(checkHttps('foreign'))

ERC20_ABI,
  ERC677_BRIDGE_TOKEN_ABI,
  getTokenType,
  getPastEvents,
  ZERO_ADDRESS
} = require('../../commons')
const { normalizeEventInformation } = require('./message')
const { filterTransferBeforeES } = require('./tokenUtils')

const {
  COMMON_HOME_RPC_URL,
  COMMON_FOREIGN_RPC_URL,
  COMMON_HOME_BRIDGE_ADDRESS,
  COMMON_FOREIGN_BRIDGE_ADDRESS
} = process.env
const MONITOR_HOME_START_BLOCK = toBN(Number(process.env.MONITOR_HOME_START_BLOCK) || 0)
const MONITOR_FOREIGN_START_BLOCK = toBN(Number(process.env.MONITOR_FOREIGN_START_BLOCK) || 0)

const homeProvider = new Web3.providers.HttpProvider(COMMON_HOME_RPC_URL)
const web3Home = new Web3(homeProvider)

const foreignProvider = new Web3.providers.HttpProvider(COMMON_FOREIGN_RPC_URL)
const web3Foreign = new Web3(foreignProvider)

const { getBlockNumber } = require('./contract')

async function main(mode) {
  const homeErcBridge = new web3Home.eth.Contract(HOME_ERC_TO_ERC_ABI, COMMON_HOME_BRIDGE_ADDRESS)
  const bridgeMode = mode || (await getBridgeMode(homeErcBridge))
  const { HOME_ABI, FOREIGN_ABI } = getBridgeABIs(bridgeMode)
  const homeBridge = new web3Home.eth.Contract(HOME_ABI, COMMON_HOME_BRIDGE_ADDRESS)
  const foreignBridge = new web3Foreign.eth.Contract(FOREIGN_ABI, COMMON_FOREIGN_BRIDGE_ADDRESS)

async function getLastProcessedBlock() {
  const result = await redis.get(lastBlockRedisKey)
  logger.debug({ fromRedis: result, fromConfig: lastProcessedBlock.toString() }, 'Last Processed block obtained')
  lastProcessedBlock = result ? toBN(result) : lastProcessedBlock
}

async function getLastProcessedBlock() {
  const result = await redis.get(lastBlockRedisKey)
  logger.debug(
    { fromRedis: result, fromConfig: lastProcessedBlock.toString() },
    'Last Processed block obtained'
  )
  lastProcessedBlock = result ? toBN(result) : lastProcessedBlock
}

ERC677_BRIDGE_TOKEN_ABI,
  getTokenType,
  getPastEvents,
  ZERO_ADDRESS
} = require('../../commons')
const { normalizeEventInformation } = require('./message')
const { filterTransferBeforeES } = require('./tokenUtils')

const {
  COMMON_HOME_RPC_URL,
  COMMON_FOREIGN_RPC_URL,
  COMMON_HOME_BRIDGE_ADDRESS,
  COMMON_FOREIGN_BRIDGE_ADDRESS
} = process.env
const MONITOR_HOME_START_BLOCK = toBN(Number(process.env.MONITOR_HOME_START_BLOCK) || 0)
const MONITOR_FOREIGN_START_BLOCK = toBN(Number(process.env.MONITOR_FOREIGN_START_BLOCK) || 0)

const homeProvider = new Web3.providers.HttpProvider(COMMON_HOME_RPC_URL)
const web3Home = new Web3(homeProvider)

const foreignProvider = new Web3.providers.HttpProvider(COMMON_FOREIGN_RPC_URL)
const web3Foreign = new Web3(foreignProvider)

const { getBlockNumber } = require('./contract')

async function main(mode) {
  const homeErcBridge = new web3Home.eth.Contract(HOME_ERC_TO_ERC_ABI, COMMON_HOME_BRIDGE_ADDRESS)
  const bridgeMode = mode || (await getBridgeMode(homeErcBridge))
  const { HOME_ABI, FOREIGN_ABI } = getBridgeABIs(bridgeMode)
  const homeBridge = new web3Home.eth.Contract(HOME_ABI, COMMON_HOME_BRIDGE_ADDRESS)
  const foreignBridge = new web3Foreign.eth.Contract(FOREIGN_ABI, COMMON_FOREIGN_BRIDGE_ADDRESS)
  const v1Bridge = bridgeMode === BRIDGE_MODES.NATIVE_TO_ERC_V1

eventContractAddress: process.env.COMMON_HOME_BRIDGE_ADDRESS,
  eventAbi: homeAbi,
  bridgeContractAddress: process.env.COMMON_HOME_BRIDGE_ADDRESS,
  bridgeAbi: homeAbi,
  pollingInterval: process.env.ORACLE_HOME_RPC_POLLING_INTERVAL,
  startBlock: toBN(process.env.ORACLE_HOME_START_BLOCK || 0),
  web3: web3Home
}

const foreignConfig = {
  eventContractAddress: process.env.COMMON_FOREIGN_BRIDGE_ADDRESS,
  eventAbi: foreignAbi,
  bridgeContractAddress: process.env.COMMON_FOREIGN_BRIDGE_ADDRESS,
  bridgeAbi: foreignAbi,
  pollingInterval: process.env.ORACLE_FOREIGN_RPC_POLLING_INTERVAL,
  startBlock: toBN(process.env.ORACLE_FOREIGN_START_BLOCK || 0),
  web3: web3Foreign
}

module.exports = {
  bridgeConfig,
  homeConfig,
  foreignConfig,
  id
}