simulation.ts

import { Chain, Common } from "@nomicfoundation/ethereumjs-common";
import { TransactionFactory } from "@nomicfoundation/ethereumjs-tx";
import { VM } from "@nomicfoundation/ethereumjs-vm";
import { ForkBlockchain } from "hardhat/internal/hardhat-network/provider/fork/ForkBlockchain";
import { ForkStateManager } from "hardhat/internal/hardhat-network/provider/fork/ForkStateManager";
import { makeForkClient } from "hardhat/internal/hardhat-network/provider/utils/makeForkClient";

const JSON_RPC_URL = "https://rpc.ankr.com/eth";

async function simulateTx(signedTx: string) {
  const tx = TransactionFactory.fromSerializedData(Buffer.from(signedTx.substring(2), "hex"));

  const common = new Common({ chain: Chain.Mainnet });
  const { forkClient, forkBlockNumber } = await makeForkClient({
    jsonRpcUrl: JSON_RPC_URL,
  });
  const stateManager = new ForkStateManager(forkClient, forkBlockNumber);
  const blockchain = new ForkBlockchain(forkClient, forkBlockNumber, common);
  const vm = await VM.create({ common, stateManager, blockchain });

  return vm.runTx({ tx });
}

export { simulateTx };