index.js

#! /usr/local/bin/node

// ERC-20 transfers between L1 and L2 using the Optimism SDK

const ethers = require("ethers")
const optimismSDK = require("@eth-optimism/sdk")
require('dotenv').config()


const mnemonic = process.env.MNEMONIC

const words = process.env.MNEMONIC.match(/[a-zA-Z]+/g).length
validLength = [12, 15, 18, 24]
if (!validLength.includes(words)) {
   console.log(`The mnemonic (${process.env.MNEMONIC}) is the wrong number of words`)
   process.exit(-1)
}

const l1Url = `https://rpc.tanenbaum.io/`
const l2Url = `https://rpc.ankr.com/rollux_testnet/${process.env.L2_ANKR_API_KEY}`


// Contract addresses for OPTb tokens, taken
// from https://github.com/ethereum-optimism/ethereum-optimism.github.io/blob/master/data/OUTb/data.json
const erc20Addrs = {
  l1Addr: "0x77776E8e71FE900cF8f5e49E5d98558198CE2D1d",
  l2Addr: "0x3e7eF8f50246f725885102E8238CBba33F276747"
}    // erc20Addrs

// To learn how to deploy an L2 equivalent to an L1 ERC-20 contract,
// see here:
// https://github.com/ethereum-optimism/optimism-tutorial/tree/main/standard-bridge-standard-token


// Global variable because we need them almost everywhere
let crossChainMessenger
let l1ERC20, l2ERC20    // OUTb contracts to show ERC-20 transfers
let ourAddr             // The address of the signer we use.


// Get signers on L1 and L2 (for the same address). Note that
// this address needs to have SYS on it, both on Rollux and
// Syscoin.
const getSigners = async () => {
    const l1RpcProvider = new ethers.providers.JsonRpcProvider(l1Url)
    const l2RpcProvider = new ethers.providers.JsonRpcProvider(l2Url)
    const hdNode = ethers.utils.HDNode.fromMnemonic(mnemonic)
    const privateKey = hdNode.derivePath(ethers.utils.defaultPath).privateKey
    const l1Wallet = new ethers.Wallet(privateKey, l1RpcProvider)
    const l2Wallet = new ethers.Wallet(privateKey, l2RpcProvider)

    return [l1Wallet, l2Wallet]
}   // getSigners



// The ABI fragment for the contract. We only need to know how to do two things:
// 1. Get an account's balance
// 2. Call the faucet to get more (only works on L1). Of course, production
//    ERC-20 tokens tend to be a bit harder to acquire.
const erc20ABI = [
  // balanceOf
  {
    constant: true,
    inputs: [{ name: "_owner", type: "address" }],
    name: "balanceOf",
    outputs: [{ name: "balance", type: "uint256" }],
    type: "function",
  },
  // faucet
  {
    inputs: [],
    name: "faucet",
    outputs: [],
    stateMutability: "nonpayable",
    type: "function"
  }
]    // erc20ABI



const setup = async() => {
  const [l1Signer, l2Signer] = await getSigners()
  ourAddr = l1Signer.address
  crossChainMessenger = new optimismSDK.CrossChainMessenger({
      l1ChainId: 5700,   // Syscoin Tanenbaum value, 57 for mainnet
      l2ChainId: 57000,  // Rollux Tanenbaum value, 570 for mainnet
      l1SignerOrProvider: l1Signer,
      l2SignerOrProvider: l2Signer,
      bedrock: true
  })
  l1ERC20 = new ethers.Contract(erc20Addrs.l1Addr, erc20ABI, l1Signer)
  l2ERC20 = new ethers.Contract(erc20Addrs.l2Addr, erc20ABI, l2Signer)
}    // setup



const reportERC20Balances = async () => {
  const l1Balance = (await l1ERC20.balanceOf(ourAddr)).toString().slice(0,-18)
  const l2Balance = (await l2ERC20.balanceOf(ourAddr)).toString().slice(0,-18)
  console.log(`OUTb on L1:${l1Balance}     OUTb on L2:${l2Balance}`)

  if (l1Balance != 0) {
    return
  }

  console.log(`You don't have enough OUTb on L1. Let's call the faucet to fix that`)
  const tx = (await l1ERC20.faucet())
  console.log(`Faucet tx: ${tx.hash}`)
  console.log(`\tMore info: https://tanenbaum.io/tx/${tx.hash}`)
  await tx.wait()
  const newBalance = (await l1ERC20.balanceOf(ourAddr)).toString().slice(0,-18)
  console.log(`New L1 OUTb balance: ${newBalance}`)
}    // reportERC20Balances




const oneToken = BigInt(1e18)


const depositERC20 = async () => {

  console.log("Deposit ERC20")
  await reportERC20Balances()
  const start = new Date()

  // Need the l2 address to know which bridge is responsible
  const allowanceResponse = await crossChainMessenger.approveERC20(
    erc20Addrs.l1Addr, erc20Addrs.l2Addr, oneToken)
  await allowanceResponse.wait()
  console.log(`Allowance given by tx ${allowanceResponse.hash}`)
  console.log(`\tMore info: https://tanenbaum.io/tx/${allowanceResponse.hash}`)
  console.log(`Time so far ${(new Date()-start)/1000} seconds`)

  const response = await crossChainMessenger.depositERC20(
    erc20Addrs.l1Addr, erc20Addrs.l2Addr, oneToken)
  console.log(`Deposit transaction hash (on L1): ${response.hash}`)
  console.log(`\tMore info: https://tanenbaum.io/tx/${response.hash}`)
  await response.wait()
  console.log("Waiting for status to change to RELAYED")
  console.log(`Time so far ${(new Date()-start)/1000} seconds`)
  await crossChainMessenger.waitForMessageStatus(response.hash,
                                                  optimismSDK.MessageStatus.RELAYED)

  await reportERC20Balances()
  console.log(`depositERC20 took ${(new Date()-start)/1000} seconds\n\n`)
}     // depositERC20()



const withdrawERC20 = async () => {

  console.log("Withdraw ERC20")
  const start = new Date()
  await reportERC20Balances()

  const response = await crossChainMessenger.withdrawERC20(
    erc20Addrs.l1Addr, erc20Addrs.l2Addr, oneToken)
  console.log(`Transaction hash (on L2): ${response.hash}`)
  console.log(`\tFor more information: https://rollux.tanenbaum.io/tx/${response.hash}`)
  await response.wait()

  console.log("Waiting for status to be READY_TO_PROVE")
  console.log(`Time so far ${(new Date()-start)/1000} seconds`)
  await crossChainMessenger.waitForMessageStatus(response.hash,
    optimismSDK.MessageStatus.READY_TO_PROVE)
  console.log(`Time so far ${(new Date()-start)/1000} seconds`)
  await crossChainMessenger.proveMessage(response.hash)


  console.log("In the challenge period, waiting for status READY_FOR_RELAY")
  console.log(`Time so far ${(new Date()-start)/1000} seconds`)
  await crossChainMessenger.waitForMessageStatus(response.hash,
                                                optimismSDK.MessageStatus.READY_FOR_RELAY)
  console.log("Ready for relay, finalizing message now")
  console.log(`Time so far ${(new Date()-start)/1000} seconds`)
  await crossChainMessenger.finalizeMessage(response.hash)

  console.log("Waiting for status to change to RELAYED")
  console.log(`Time so far ${(new Date()-start)/1000} seconds`)
  await crossChainMessenger.waitForMessageStatus(response,
    optimismSDK.MessageStatus.RELAYED)
  await reportERC20Balances()
  console.log(`withdrawERC20 took ${(new Date()-start)/1000} seconds\n\n\n`)
}     // withdrawERC20()




const main = async () => {
    await setup()
    await depositERC20()
    await withdrawERC20()
}  // main



main().then(() => process.exit(0))
  .catch((error) => {
    console.error(error)
    process.exit(1)
  })