Sending a Batch of Transactions

One Click Batching With Atomicity

With batching functionality, you can send multiple user actions in a single native transaction on Smart Account.

In this example, the user approves amount of USDC to the Hyphen Liquidity Pool. Then user adds liquidity to the pool by calling the addTokenLiquidity function that transfers part of the approved USDC from the user's Smart Account to itself.

USDCAddress.approve and hyphenLiquidityPoolAddress.addTokenLiquidity methods calls are batched together and executed as a single on-chain transaction.

In order to create a batch of transactions, just create a Transaction Request array and push individual transaction requests (destination contract and encoded data for method to be called) to it.

// Init Smart account instance

const usdcAddress = <USDC TOKEN>
const hyphenLiquidityPoolAddress = <LP_ADDRESS> // spender

// create an array of txs 
const txs = []

const erc20Interface = new ethers.utils.Interface([
  'function approve(address _to, uint256 _value)'
])

// Encode an ERC-20 token approval. User approves the amount of tokens to the Hyphen LP
const data = erc20Interface.encodeFunctionData(
  'approve', [hyphenLiquidityPoolAddress, amount]
)

const tx1 = {
  to: usdcAddress 
  data: data
}

txs.push(tx1)

const hyphenLPTx =
    await hyphenContract.populateTransaction.addTokenLiquidity(
      usdcAddress,
      ethers.BigNumber.from("1000000") // providing liquidity for 1 USDC
  );

const tx2 = {
  to: hyphenLiquidityPoolAddress,
  data: hyphenLPTx.data,
};

txs.push(tx2);

// Fee Abstraction and Dispatching

// 1. Gasless 
const txResponse = await smartAccount.sendTransactionBatch({ transactions: txs });
console.log('userOp Hash', txResponse);
const txReciept = await txResponse.wait();
console.log('Tx hash', txReciept.transactionHash);

// 2. User Self Refund (Native / ERC20)
const feeQuotes = await smartAccount.getFeeQuotesForBatch({
  transactions: txs,
});

// Choose a fee quote of your choice provided by the relayer
const transaction = await smartAccount.createUserPaidTransactionBatch({
  transactions: txnArray,
  feeQuote: feeQuotes[1],
});

// optional
let gasLimit: GasLimit = {
  hex: "0x1E8480",
  type: "hex",
};

// send transaction internally calls signTransaction and sends it to connected relayer
const txHash = await smartAccount.sendUserPaidTransaction({
  tx: transaction,
  gasLimit,
});

info

If you have any questions please post them on the Biconomy SDK Forum