How to set gas price / gas limit for contract function without parameters

[onemanking]

Smart contract function does not receive any parameters and I want to set up gas limit and gas price before send.
I tried to follow the doc and still not successful

here is my code

    const contractWithSigner = reinvestContract.connect(wallet);
    const options = { gasLimit: gasLimit, gasPrice: gasPrice };
    const transaction = await contractWithSigner.reinvest([], options); // <<
    const receipt = await getTransactionReceipt(transaction);

also this

    const contractWithSigner = reinvestContract.connect(wallet);
    const options = { gasLimit: gasLimit, gasPrice: gasPrice };
    const transaction = await contractWithSigner.reinvest(null, options); // <<
    const receipt = await getTransactionReceipt(transaction);

and this

    const contractWithSigner = reinvestContract.connect(wallet);
    const options = { gasLimit: gasLimit, gasPrice: gasPrice };
    const transaction = await contractWithSigner.reinvest(options); // <<
    const receipt = await getTransactionReceipt(transaction);

Can somebody help me with this?

Thank you

[zemse]

The third one should work. Relevant docs: if a contract function takes n arguments, then the n+1th arg can be optionally passed as the overrides object.

contractWithSigner.reinvest({ gasLimit: gasLimit, gasPrice: gasPrice });

[onemanking]

Thank you

[Centori]

Hi,im just trying to get the hang this and ,I wonder how can i incorporate a function that resends a higher gas rate thats equal to or greater than the profit?Thanks.

if (!shouldTrade) return;

  const gasLimit = await sushiEthDai.estimateGas.swap(
    !shouldStartEth ? DAI_TRADE : 0,
    shouldStartEth ? ETH_TRADE : 0,
    flashLoanerAddress,
    ethers.utils.toUtf8Bytes('1'),
  );

  const gasPrice = await wallet.getGasPrice();

  const gasCost = Number(ethers.utils.formatEther(gasPrice.mul(gasLimit)));
  ;


  const shouldSendTx = shouldStartEth
    ? (gasCost / ETH_TRADE) < spread
    : (gasCost / (DAI_TRADE / priceUniswap)) < spread;

  // don't trade if gasCost is higher than the spread
  if (!shouldSendTx) return;

  const options = {
    gasPrice,
    gasLimit,
  };
  const tx = await sushiEthDai.swap(
    !shouldStartEth ? DAI_TRADE : 0,
    shouldStartEth ? ETH_TRADE : 0,
    flashLoanerAddress,
    ethers.utils.toUtf8Bytes('1'), options,
  );

[zemse]

how can i incorporate a function that resends a higher gas rate thats equal to or greater than the profit?

What do you mean by profit? From your code, I am guessing that you are doing an arbitrage bot.

This line Number(ethers.utils.formatEther(gasPrice.mul(gasLimit))); here you should not work with JS numbers as they have 53 precision bits, which probably will not be enough. You should do the arithmetic and comparisons in BigNumber.

gasPrice.mul(gasLimit).lt(spread) // true if spread is big

Also note that the check does not always guarantee profit. The moment when you are estimating / querying the prices, and while the swap is actually executing, if someone front-run you, then you might be at a loss.

[Centori]

Yes Its an arbitrage bot,problem is I keep getting this error:

TypeError: Cannot read property 'toHexString' of undefined

the full code is below,Im trying to figure out what Im getting wrong for it to work.

require('dotenv').config();

const privateKey = process.env.PRIVATE_KEY;
// your contract address
const flashLoanerAddress = process.env.FLASH_LOANER;

const { ethers } = require('ethers');

// uni/sushiswap ABIs
const UniswapV2Pair = require('./abis/IUniswapV2Pair.json');
const UniswapV2Factory = require('./abis/IUniswapV2Factory.json');

// use your own Infura node in production
const provider = new ethers.providers.InfuraProvider('mainnet', process.env.INFURA_KEY);

const wallet = new ethers.Wallet(privateKey, provider);

const ETH_TRADE = 10;
const DAI_TRADE = 3500;

const runBot = async () => {
const sushiFactory = new ethers.Contract(
'0xC0AEe478e3658e2610c5F7A4A2E1777cE9e4f2Ac',
UniswapV2Factory.abi, wallet,
);
const uniswapFactory = new ethers.Contract(
'0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f',
UniswapV2Factory.abi, wallet,
);
const daiAddress = '0x6b175474e89094c44da98b954eedeac495271d0f';
const wethAddress = '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2';

let sushiEthDai;
let uniswapEthDai;

const loadPairs = async () => {
sushiEthDai = new ethers.Contract(
await sushiFactory.getPair(wethAddress, daiAddress),
UniswapV2Pair.abi, wallet,
);
uniswapEthDai = new ethers.Contract(
await uniswapFactory.getPair(wethAddress, daiAddress),
UniswapV2Pair.abi, wallet,
);
};

await loadPairs();

provider.on('block', async (blockNumber) => {
try {
console.log(blockNumber);

  const sushiReserves = await sushiEthDai.getReserves();
  const uniswapReserves = await uniswapEthDai.getReserves();

  const reserve0Sushi = Number(ethers.utils.formatUnits(sushiReserves[0], 18));

  const reserve1Sushi = Number(ethers.utils.formatUnits(sushiReserves[1], 18));

  const reserve0Uni = Number(ethers.utils.formatUnits(uniswapReserves[0], 18));
  const reserve1Uni = Number(ethers.utils.formatUnits(uniswapReserves[1], 18));

  const priceUniswap = reserve0Uni / reserve1Uni;
  const priceSushiswap = reserve0Sushi / reserve1Sushi;

  const shouldStartEth = priceUniswap < priceSushiswap;
  const spread = Math.abs((priceSushiswap / priceUniswap - 1) * 100) - 0.6;

  const shouldTrade = spread > (
    (shouldStartEth ? ETH_TRADE : DAI_TRADE)
     / Number(
       ethers.utils.formatEther(uniswapReserves[shouldStartEth ? 1 : 0]),
     ));

  console.log(`UNISWAP PRICE ${priceUniswap}`);
  console.log(`SUSHISWAP PRICE ${priceSushiswap}`);
  console.log(`PROFITABLE? ${shouldTrade}`);
  console.log(`CURRENT SPREAD: ${(priceSushiswap / priceUniswap - 1) * 100}%`);
  console.log(`ABSLUTE SPREAD: ${spread}`);

  if (!shouldTrade) return;

  const gasLimit = await sushiEthDai.estimateGas.swap(
    !shouldStartEth ? DAI_TRADE : 0,
    shouldStartEth ? ETH_TRADE : 0,
    flashLoanerAddress,
    ethers.utils.toUtf8Bytes('1'),
  );

  const gasPrice = await wallet.getGasPrice();

  const gasCost = Number(ethers.utils.formatEther(gasPrice.mul(gasLimit)));

  const shouldSendTx = shouldStartEth
    ? (gasCost / ETH_TRADE) < spread
    : (gasCost / (DAI_TRADE / priceUniswap)) < spread;

  // don't trade if gasCost is higher than the spread
  if (!shouldSendTx) return;

  const options = {
    gasPrice,
    gasLimit,
  };
  const tx = await sushiEthDai.swap(
    !shouldStartEth ? DAI_TRADE : 0,
    shouldStartEth ? ETH_TRADE : 0,
    flashLoanerAddress,
    ethers.utils.toUtf8Bytes('1'), options,
  );

  console.log('ARBITRAGE EXECUTED! PENDING TX TO BE MINED');
  console.log(tx);

  await tx.wait();

  console.log('SUCCESS! TX MINED');
} catch (err) {
  console.error(err);
}

});
};

console.log('Bot started!');

runBot();

[zemse]

@Centori that's a lot of code to execute in my head xD. But looking at the error Cannot read property 'toHexString' of undefined it seems there is a typo somewhere in the code (like obj.incoerctPropName) which is being passed somewhere. Do you get a stack trace? It allows to pin point the line number where you can look for.

[Centori]

Hey Man,yes its an arbitrage bot,I m just checking out a VScode tutorial on Node.js and Debugging.Could that be helpful in getting this to run?Thanks

…

On Thu, Sep 16, 2021 at 4:21 PM soham ***@***.***> wrote: @Centori <https://github.com/Centori> that's a lot of code to execute in my head xD. But looking at the error Cannot read property 'toHexString' of undefined it seems there is a typo somewhere in the code (like obj.incoerctPropName) which is being passed somewhere. Do you get a stack trace? It allows to pin point the line number where you can look for. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1452 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AKCW2QSC2RXKSXHXDU74JO3UCIDQFANCNFSM42ZO35VQ> .