bot.ts

var path = require('path')
var filename = path.dirname('config.json') + '\\config.json'

const ethers = require('ethers');
const json = require(filename)

const addresses = {
  WBNB: json.data.WBNB,
  factory: json.data.factory,
  router: json.data.router,
  recipient: json.data.recipient
}

const mnemonic = ''

const provider = new ethers.providers.WebSocketProvider('wss://apis.ankr.com/wss/')
const wallet = ethers.Wallet.fromMnemonic(mnemonic);
const account = wallet.connect(provider);
const factory = new ethers.Contract(
  addresses.factory,
  ['event PairCreated(address indexed token0, address indexed token1, address pair, uint)'],
  account
)
const router = new ethers.Contract(
  addresses.router,
  [
    'function getAmountsOut(uint amountIn, address[] memory path) public view returns (uint[] memory amounts)',
    'function swapExactTokensForTokens(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external returns (uint[] memory amounts)'
  ],
  account
)

const wbnb = new ethers.Contract(
  addresses.WBNB,
  [
    'function approve(address spender) public returns(bool)',
  ],
  account
)

const init = async () => {
  const tx = await wbnb.approve(
    router.address,
    ethers.constants.MaxUint256
  )
  const receipt = await tx.wait()
  console.log('Transaction receipt')
  console.log(receipt)
}

factory.on('PairCreated', async (token0, token1, pairAddress) => {
  console.log(`
    New pair detected
    =================
    token0: ${token0}
    token1: ${token1}
    pairAddress: ${pairAddress}
  `);

  let tokenIn, tokenOut;
  if(token0 === addresses.WBNB) {
    tokenIn = token0
    tokenOut = token1
  }

  if(token1 == addresses.WBNB) {
    tokenIn = token1 
    tokenOut = token0
  }

  if(typeof tokenIn === 'undefined') {
    return
  }

  const amountIn = ethers.utils.parseUnits('0.001', 'ether');
  const amounts = await router.getAmountsOut(amountIn, [tokenIn, tokenOut])
  const amountOutMin = amounts[1].sub(amounts[1].div(10))
  console.log(`
    Buying new token
    =================
    tokenIn: ${amountIn.toString()} ${tokenIn} (WBNB)
    tokenOut: ${amounOutMin.toString()} ${tokenOut}
  `)
  const tx = await router.swapExactTokensForTokens(
    amountIn,
    amountOutMin,
    [tokenIn, tokenOut],
    addresses.recipient,
    Date.now() + 1000 * 60 * 10, // 10 minutes
    {
        gasPrice: 5000000000,
        gasLimit: 1000000
    }
  )
  const receipt = await tx.wait()
  console.log('Transaction receipt')
  console.log(receipt)
})

init().catch(err => { console.log(err) })