@xdapps/ethers-event-listeners-lib

Ethereum Event Listeners for ERC-20, ERC-721, & ERC-1155 transfer events

This is a basic wrapper around Ethers.js with static methods for listening to transfer events on ERC-20, ERC-721, or ERC-1155 contracts. This was created as a basic example to demonstrate how to listen to events and take action in real time.

Basics

1. Import the protocol you want to interact with.
2. Instantiate listeners with an array of contract address and an Ethers provider.
3. Start the listeners and pass in a callback function to be executed upon each transfer event found.

How To Use

npm install @xdapps/ethers-event-listeners-lib
or
yarn add @xdapps/ethers-event-listeners-lib

import {ERC20TransferListeners, ERC20TransferEvent} from "@xdapps/ethers-event-listeners-lib";

const listOfERC20Contracts = ["0x.....", "0x...."]; // List of contracts to listen to
const provider = new ethers.providers.JsonRpcProvider("RPC_URL_ADDRESS");

const callBackForTransferEvent = (eventData: ERC20TransferEvent){
// Your code to handle the transfer event goes here.....
//......
//......
}
const listeners = ERC20TransferListeners.getInstance(listOfERC20Contracts, provider);
await listeners.start(callBackForTransferEvent);

Poll for Redundancy

Sometimes, the real time listeners can miss events, it's not common, but for redundancy, I've built back up "pollers" that allow you to go behind the listeners and poll specific block ranges for specific events.

I prefer to have the real time listeners running and then poll every 3-5 minutes to ensure no events are missed.

import {ERC20TransferPoller, ERC20TransferEvent} from "@xdapps/ethers-event-listeners-lib";

const contractToPoll = "0x....."; // Address of contract to poll
const provider = new ethers.providers.JsonRpcProvider("RPC_URL_ADDRESS");
const lastBlockPolled = 10000;
const maxBlocksPerPoll = 500;

const callBackForTransferEvent = (eventData: ERC20TransferEvent){
// Your code to handle the transfer event goes here.....
//......
//......
}
const poller = new ERC20TransferPoller(contractToPoll, lastBlockPolled, maxBlocksPerPoll);
await poller.pollBlocks(provider, callBackForTransferEvent);