JavaScript build ethereum create2 address (counterfactual smart contract address)

build_create2_address.js

function buildCreate2Address(creatorAddress, saltHex, byteCode) {
  const parts = [
    'ff',
    creatorAddress.slice(2),
    saltHex.slice(2),
    web3.utils.sha3(byteCode).slice(2),
  ]

  const partsHash = web3.utils.sha3(`0x${parts.join('')}`)
  return `0x${partsHash.slice(-40)}`.toLowerCase()
}

function numberToUint256(value) {
  try {
    const hex = value.toString(16)
    return `0x${'0'.repeat(64 - hex.length)}${hex}`
  } catch (err) {}

  return null
}

const {bytecode} = require('./build/contracts/Channel.json')
const creatorAddress = '0xc776E37126Bc5fa0e12e775416bB59E4884F8B2f'
const salt = 1

const contractAddress = buildCreate2Address(
  creatorAddress,
  numberToUint256(salt),
  bytecode,
)

console.log(contractAddress) // 0x3ecba4f4fb671afef7fd2489923dc3b60fc3853a