Simulate a transaction

const handleSimulateTransaction = async () => {
  // First, construct a transaction.
  const transaction = {
    to: '0xRecipientAddressHere', // {string} The recipient address.
    value: '0x10DE4A2A',  // {?string} The value to be sent in Wei.
    data: undefined,  // {?string} Data for the transaction (for contract interactions).
    maxFeePerGas: undefined, // {?string} Maximum fee per gas.
    maxPriorityFeePerGas: undefined, // {?string} Maximum priority fee per gas.
    gas: undefined, // {?string} The gas limit.
    gasPrice: undefined // {?string} Gas price in Wei.
  };

  // Next, simulate the transaction.
  const chainId = 'eip155:1'
  const simulatedResult = await portal.simulateTransaction(chainId, transaction);

  // Finally, you can handle or display the simulation results as needed.
  if (simulatedResult.error) {
    console.error("Transaction Error:", simulatedResult.error.message);
  } else if (simulatedResult.requestError) {
    console.error("Request Error:", simulatedResult.requestError.message);
  } else {
    console.log("Simulated Transaction Results:", simulatedResult.changes);
  }
}