tokenbridge/monitor/utils/contract.js

const { toBN } = require('web3').utils

const ONE = toBN(1)
const TWO = toBN(2)

async function getPastEvents({ contract, event, fromBlock, toBlock, options }) {
  let events
  try {
    events = await contract.getPastEvents(event, {
      ...options,
      fromBlock,
      toBlock
    })
  } catch (e) {
    if (e.message.includes('query returned more than 1000 results')) {
      const middle = fromBlock.add(toBlock).divRound(TWO)
      const middlePlusOne = middle.add(ONE)

      const firstHalfEvents = await getPastEvents({
        contract,
        event,
        fromBlock,
        toBlock: middle,
        options
      })
      const secondHalfEvents = await getPastEvents({
        contract,
        event,
        fromBlock: middlePlusOne,
        toBlock,
        options
      })
      events = [...firstHalfEvents, ...secondHalfEvents]
    } else {
      throw new Error(e)
    }
  }
  return events
}

const getBlockNumberCall = web3 => web3.eth.getBlockNumber()

async function getBlockNumber(web3Home, web3Foreign) {
  return (await Promise.all([web3Home, web3Foreign].map(getBlockNumberCall))).map(toBN)
}

module.exports = {
  getPastEvents,
  getBlockNumber
}