Listening/Filtering events using ethersjs

filtering-events-ethers.js

const { ethers } = require("hardhat");

const main = async () => {
  const yourContract = await ethers.getContractAt(
    "YourContract",
    "0x5FC8d32690cc91D4c39d9d3abcBD16989F875707"
  );
  // Note that we filter for SetPurpose events that have "filterme" as purpose
  const filter = yourContract.filters.SetPurpose(null, "filterme");
  yourContract.on(filter, (sender, purpose, event) => {
    console.log(event);
  });
};

main();

YourContract.sol

// This is the basic scaffold-eth contract. Note the SetPurpose event :)

pragma solidity >=0.8.0 <0.9.0;

import "hardhat/console.sol";

contract YourContract {

  // `indexed` is necessary to filter!
  event SetPurpose(address sender, string indexed purpose);

  string public purpose = "Building Unstoppable Apps!!!";

  constructor() {
    // what should we do on deploy?
  }

  function setPurpose(string memory newPurpose) public {
      purpose = newPurpose;
      console.log(msg.sender,"set purpose to",purpose);
      emit SetPurpose(msg.sender, purpose);
  }
}