uniswapTrader.js

const { ethers } = require('ethers');
const {
  abi: IUniswapV3PoolABI,
} = require('@uniswap/v3-core/artifacts/contracts/interfaces/IUniswapV3Pool.sol/IUniswapV3Pool.json');
const {
  abi: SwapRouterABI,
} = require('@uniswap/v3-periphery/artifacts/contracts/interfaces/ISwapRouter.sol/ISwapRouter.json');
const { getPoolImmutables, getPoolState } = require('./helpers');
const {
  abi: ERC20ABI,
} = require('@openzeppelin/contracts/build/contracts/ERC20.json');

require('dotenv').config();

const INFURA_URL_TESTNET = process.env.INFURA_URL_TESTNET;
const WALLET_ADDRESS = process.env.WALLET_ADDRESS;
const WALLET_SECRET = process.env.WALLET_SECRET;

const provider = new ethers.providers.JsonRpcProvider(INFURA_URL_TESTNET); // Ropsten
const poolAddress = '0x4D7C363DED4B3b4e1F954494d2Bc3955e49699cC'; // UNI/WETH
const swapRouterAddress = '0xE592427A0AEce92De3Edee1F18E0157C05861564';

const name0 = 'Wrapped Ether';
const symbol0 = 'WETH';
const decimals0 = 18;
const address0 = '0xc778417e063141139fce010982780140aa0cd5ab';

const name1 = 'Uniswap Token';
const symbol1 = 'UNI';
const decimals1 = 18;
const address1 = '0x1f9840a85d5af5bf1d1762f925bdaddc4201f984';

async function main() {
  const poolContract = new ethers.Contract(
    poolAddress,
    IUniswapV3PoolABI,
    provider
  );

  // grab data
  const immutables = await getPoolImmutables(poolContract);
  const state = await getPoolState(poolContract);

  // create & connect wallet
  const wallet = new ethers.Wallet(WALLET_SECRET);
  const connectedWallet = wallet.connect(provider);

  // console.log('wallet', connectedWallet);

  const swapRouterContract = new ethers.Contract(
    swapRouterAddress,
    SwapRouterABI,
    provider
  );

  const inputAmount = 0.001;
  // .001 ether => 1 000 000 000 000 000
  const amountIn = ethers.utils.parseUnits(inputAmount.toString(), decimals0);

  const approvalAmount = (amountIn * 1000).toString();
  const tokenContract0 = new ethers.Contract(address0, ERC20ABI, provider);
  const approvalResponse = await tokenContract0
    .connect(connectedWallet)
    .approve(swapRouterAddress, approvalAmount);

  // console.log('approve: ', approvalResponse);

  const params = {
    tokenIn: immutables.token1,
    tokenOut: immutables.token0,
    fee: immutables.fee,
    recipient: WALLET_ADDRESS,
    deadline: Math.floor(Date.now() / 1000) + 60 * 10,
    amountIn: amountIn,
    amountOutMinimum: 0,
    sqrtPriceLimitX96: 0,
  };

  const transaction = await swapRouterContract
    .connect(connectedWallet)
    .exactInputSingle(params, {
      gasLimit: ethers.utils.hexlify(1000000),
      // gasPrice: 10000000000,
    });

  console.log('transaction', transaction);
}

main();