DOP_price_monitor.js

const ethers = require('ethers');

const provider = new ethers.providers.JsonRpcProvider('https://bsc-dataseed.binance.org/');

// you can find pair address from Factory Contract, method getPair(token1Addr, token2Addr).
let Contract = {
    PancakePair: new ethers.Contract('0xb694ec7C2a7C433E69200b1dA3EBc86907B4578B',['function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast)'], provider),
    TwindexPair: new ethers.Contract('0xC789F6C658809eED4d1769a46fc7BCe5dbB8316E',['function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast)'], provider)
}

provider.on('block', async (blockNumber) => {
    
    const pancakeReserves = await Contract.PancakePair.getReserves();
    const at_pancake =  pancakeReserves[1] / pancakeReserves[0];
    console.log(`Pancake 1 DOP = ${at_pancake} BUSD`);
    
    const twindexReserves = await Contract.TwindexPair.getReserves();
    const at_twindex =  twindexReserves[1] / twindexReserves[0];
    console.log(`Twindex 1 DOP = ${at_twindex} BUSD`);
    
});