swap rate bot example

swap_rate.js

import { ethers } from "ethers";

// Node RPC for Ethereum, BSC, Matic
const jsonRPC = "https://bsc-dataseed1.ninicoin.io/";

// Pancakeswap V2 factory address
const factoryAddress = "0xBCfCcbde45cE874adCB698cC183deBcF17952812";

// Tokens address
const tokens = {
  BNB: "0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c",
  BUSD: "0xe9e7cea3dedca5984780bafc599bd69add087d56",
  DOLLY: "0xff54da7caf3bc3d34664891fc8f3c9b6dea6c7a5",
  USDT: "0x55d398326f99059ff775485246999027b3197955",
};

// BNB-BUSD LP token address at Twindex
const bnbBUSDLPAddr = "0x683c41b49d154ccc30887a66e52e3917f3839b09";

// Application Binary Interface
const abi = {
  factory: [
    "function getPair(address tokenA, address tokenB) external view returns (address pair)",
  ],
  lpToken: [
    "function token0() external view returns (address)",
    "function token1() external view returns (address)",
    "function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast)",
  ],
  token: [
    "function symbol() public view returns (string memory)",
    "function decimals() public view returns (uint8)",
  ],
};

// create connection to Ethereum network
const provider = new ethers.providers.JsonRpcProvider(jsonRPC);

// Show BNB/BUSD swap rate at PancakeSwap by tokens addess (ใช้วิธีเอา address ไปเสริชหา LP Address เอาจาก factory contract)
(async () => {
  // Create Pancakswap Contract client
  const pancake = new ethers.Contract(factoryAddress, abi.factory, provider);

  // Get LP Address
  const pairAddr = await pancake.getPair(tokens.BNB, tokens.BUSD);

  // Create LP Token Contract client
  const lp = new ethers.Contract(pairAddr, abi.lpToken, provider);

  // Get Tokens addresses
  let [token0Addr, token1Addr] = await Promise.all([lp.token0(), lp.token1()]);

  // Create Tokens Contract client
  const token0 = new ethers.Contract(token0Addr, abi.token, provider);
  const token1 = new ethers.Contract(token1Addr, abi.token, provider);

  // Get Tokens symbol
  let [token0Symbol, token1Symbol] = await Promise.all([
    token0.symbol(),
    token1.symbol(),
  ]);
  
  // Set interval for 5 sec 
  setInterval(async () => {
    try {
      // Get LP Reserve (จำนวนเหรียญใน LP)
      let reserves = await lp.getReserves();
      // Calulate swap rate (เอาจำนวน token1 หารด้วย จำนวน token0)
      let value = reserves[1] / reserves[0];
      console.log(`Pancake: 1 ${token0Symbol} = ${value} ${token1Symbol}`);
    } catch (err) {
      console.error(err);
    }
  }, 5000);
})();

// Show BNB/BUSD swap rate at Twindex by LP Address (หากมี LP Address อยู่แล้วจะใช้วิธีนี้)
(async () => {
  // Create LP token contract client
  const lp = new ethers.Contract(bnbBUSDLPAddr, abi.lpToken, provider);

  // Get tokens address
  let [token0Addr, token1Addr] = await Promise.all([lp.token0(), lp.token1()]);

  // Create tokens contract client
  const token0 = new ethers.Contract(token0Addr, abi.token, provider);
  const token1 = new ethers.Contract(token1Addr, abi.token, provider);

  // Get tokens symbol
  let [token0Symbol, token1Symbol] = await Promise.all([
    token0.symbol(),
    token1.symbol(),
  ]);

  // Set Interval for 5 sec 
  setInterval(async () => {
    try {
      // Get lp reserve
      let reserves = await lp.getReserves();
      // calulate swap rate
      let Value = reserves[1] / reserves[0];
      console.log(`Twindex: 1 ${token0Symbol} = ${value} ${token1Symbol}`);
    } catch (err) {
      console.error(err);
    }
  }, 5000);
})();