在 Dapp UI 中使用 Simulation RPC

export default function ConfirmSwapModal({
  /* ... */
}: {
  /* ... */
}) {
  // ...
  const modalHeader = useCallback(() => {
    return trade ? (
      <>
        <SwapModalHeader.../>
+        <Simulation trade={trade} recipient={null} allowedSlippage={allowedSlippage} />
      </>
    ) : null
  }, [/* ... */])
  //...

const Simulation = ({
  trade,
  allowedSlippage,
  recipient,
}: {
  trade: InterfaceTrade<Currency, Currency, TradeType> | undefined;
  recipient: string | null;
  allowedSlippage: Percent;
}) => {
  const { account, provider } = useWeb3React();
  const nativeCurrency = useNativeCurrency();

  const deadline = useTransactionDeadline();
  const signatureData = useERC20PermitFromTrade(trade, allowedSlippage, deadline);
  const args = useSwapCallArguments(
    trade,
    allowedSlippage,
    recipient,
    signatureData.signatureData,
    deadline,
    undefined,
  );

  const [oldBalances, setOldBalances] = useState<any[]>([]);
  const [transfers, setTransfers] = useState<any[]>([]);
  const [swap, setSwap] = useState<any>({});

  useEffect(() => {
    onSimulate();
  }, [trade, provider]);

  async function onSimulate() {
    setOldBalances([]);
    setSwap({});
    const { address, calldata, value } = args[0];
    const provider = RPC_PROVIDERS[SupportedChainId.MAINNET];

    await getCurrentBalances();
    await simulateRPC(account, address, calldata, value);
  }

  async function getCurrentBalances() {
    return Promise.all([
      provider.send('eth_getBalance', [account, 'latest']),
      provider.send('eth_call', [
        {
          to: '0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984',
          data: `0x70a0823100000000000000000000000000${stripX(account)}`,
        },
        'latest',
      ]),
    ]).then(oldBalances => {
      setOldBalances(oldBalances);
    });
  }

  async function simulateRPC(account: string, address: string, calldata: string, value: string) {
    RPC_PROVIDERS[SupportedChainId.MAINNET]
      .send('tenderly_simulateTransaction', [
        {
          from: account,
          to: address,
          data: calldata,
          value: stripHexZero(value),
        },
        'latest', // block number to simulate on
        null, // optional state overrides for involved contracts
      ])
      .then(simulationResponse => {
        console.log('Simulation Response', simulationResponse);
        setTransfers(simulationResponse.logs.filter((log: any) => log.name === 'Transfer'));
        setSwap(simulationResponse.logs.filter((log: any) => log.name === 'Swap')[0]);
      });
  }

  return (
    <>
      ...
      <SimulationDetails
        trade={trade}
        syncing={oldBalances.length == 0 && transfers.length == 0 && !!swap.inputs}
        transfers={transfers}
        oldBalances={oldBalances}
        swap={swap}
      />
    </>
  );
};