Rocket Pool rETH Deposit

This guide demonstrates how to use the Omni SDK to allow users to deposit ETH from Arbitrum into Rocket Pool on Ethereum Mainnet to mint rETH.

Since the Rocket Pool deposit contract (0xDD3f50F8A6CafbE9b31a427582963f465E745AF8) includes an onBehalfOf parameter in its deposit function (deposit(address _onBehalfOf)), we can directly specify the user's address in the useOrder call without needing withExecAndTransfer.

Concepts

• onBehalfOf: The target contract's deposit function takes address _onBehalfOf. We provide the connected user's address here.
• calls Array: In the useOrder configuration (likely inside useL2Deposit), the calls array would look something like this:

  calls: [
    {
      target: ROCKET_POOL_ADDRESS,
      abi: ROCKET_POOL_ABI,
      functionName: 'deposit',
      value: quotedExpenseAmt, // ETH amount calculated by useQuote
      args: [userAddress] // Pass user address as argument
    }
  ]

• No withExecAndTransfer: Because the contract supports onBehalfOf, the simpler direct call method is used.

Code

For clarity, this example uses a simplified custom hook useL2Deposit that wraps useQuote and useOrder. The full implementation is omitted here, but it handles:

• Fetching quotes for depositing ETH from the source chain (e.g., Arbitrum) to cover the ETH expense on the destination chain (Ethereum Mainnet).
• Creating the order object with the correct parameters, including the user's address in the onBehalfOf field within the calls array.

// Simplified representation of the custom hook's usage
import { useL2Deposit } from './useL2Deposit'; // Assume this hook exists
import { parseEther } from 'viem';
import { arbitrumSepolia, holesky } from 'viem/chains';
 
const ROCKET_POOL_ADDRESS = '0xDD3f50F8A6CafbE9b31a427582963f465E745AF8'; // On Holesky
const ROCKET_POOL_ABI = [
  { inputs: [{ name: '_onBehalfOf', type: 'address' }], name: 'deposit', outputs: [], stateMutability: 'payable', type: 'function' }
] as const;
 
function RocketPoolDepositComponent() {
  const depositAmount = parseEther('0.1'); // Example amount
  const { address: userAddress } = useAccount();
 
  const { open, status, validation, isReady, isTxPending } = useL2Deposit({
    depositAmount,
    srcChainId: arbitrumSepolia.id,
    destChainId: holesky.id,
    targetContract: ROCKET_POOL_ADDRESS,
    targetAbi: ROCKET_POOL_ABI,
    targetFunctionName: 'deposit',
    targetArgs: userAddress ? [userAddress] : undefined, // Pass user address for onBehalfOf
    enabled: !!userAddress,
  });
 
  const canOpen = isReady && validation?.status === 'accepted' && !isTxPending;
 
  return (
    <div>
      {/* UI Elements similar to other deposit examples */}
      <button disabled={!canOpen} onClick={() => open?.()}>Deposit to Rocket Pool</button>
      <p>Status: {status}</p>
    </div>
  );
}