withdrawFunds.js

const { ethers } = require('hardhat');
const { providers, Wallet } = require('ethers');
const {
  arbLog,
  requireEnvVariables,
  addCustomNetworkFromFile,
} = require('arb-shared-dependencies');
const { getArbitrumNetwork, InboxTools } = require('@arbitrum/sdk');
const { ARB_SYS_ADDRESS } = require('@arbitrum/sdk/dist/lib/dataEntities/constants');
const { ArbSys__factory } = require('@arbitrum/sdk/dist/lib/abi/factories/ArbSys__factory');
require('dotenv').config();
requireEnvVariables(['PRIVATE_KEY', 'CHAIN_RPC', 'PARENT_CHAIN_RPC']);

/**
 * Set up: instantiate wallets connected to providers
 */
const walletPrivateKey = process.env.PRIVATE_KEY;

const parentChainProvider = new providers.JsonRpcProvider(process.env.PARENT_CHAIN_RPC);
const childChainProvider = new providers.JsonRpcProvider(process.env.CHAIN_RPC);

const parentChainWallet = new Wallet(walletPrivateKey, parentChainProvider);
const childChainWallet = new Wallet(walletPrivateKey, childChainProvider);

const main = async () => {
  await arbLog('DelayedInbox withdraw funds from the parent chain (L2MSG_signedTx)');

  /**
   * Add the custom network configuration to the SDK if present
   */
  addCustomNetworkFromFile();

  /**
   * Use childChainNetwork to create an Arbitrum SDK InboxTools instance
   */
  const childChainNetwork = await getArbitrumNetwork(childChainProvider);
  const inboxTools = new InboxTools(parentChainWallet, childChainNetwork);

  /**
   * Here we use the ArbSys precompile to withdraw our funds;
   * we'll be setting it by sending it as a message from delayed inbox on the parent chain!!!
   */
  const arbSys = ArbSys__factory.connect(ARB_SYS_ADDRESS, childChainProvider);
  const arbsysIface = arbSys.interface;
  const calldata = arbsysIface.encodeFunctionData('withdrawEth', [parentChainWallet.address]);
  const transactionRequest = {
    data: calldata,
    to: ARB_SYS_ADDRESS,
    value: 1, // Only set 1 wei since it just a test tutorial, but you can set any amount
  };

  /**
   * We need to extract the transaction hash in the child chain first so we can check later if it was executed
   */
  const signedTransaction = await inboxTools.signChildTx(transactionRequest, childChainWallet);
  const transactionHash = ethers.utils.parseTransaction(signedTransaction).hash;

  /**
   * We now send the transaction through the Delayed Inbox on the parent chain
   */
  const sendMessageParentChainTransactionRequest = await inboxTools.sendChildSignedTx(
    signedTransaction,
  );
  const sendMessageParentChainTransactionReceipt =
    await sendMessageParentChainTransactionRequest.wait();
  console.log(
    `Withdraw txn initiated on the parent chain! 🙌 ${sendMessageParentChainTransactionReceipt.transactionHash}`,
  );

  /**
   * Now we successfully send the transaction to the delayed inbox on the parent chain
   * We wait for the transaction to be executed on the child chain
   */
  console.log(
    `Now we need to wait tx: ${transactionHash} to be executed on the child chain (may take ~15 minutes) ... `,
  );
  const transactionReceipt = await childChainProvider.waitForTransaction(transactionHash);
  const status = transactionReceipt.status;
  if (status == true) {
    console.log(
      `Transaction executed on the child chain!!! 🥳 After a challenge period has passed, you can go to https://bridge.arbitrum.io/ to execute your withdrawal and receive your funds!`,
    );
  } else {
    throw new Error(
      `The transaction failed to execute on the child chain. Please verify if the gas provided was enough`,
    );
  }
};

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