Continuous Event Listener Node.js Ethers.js

A JavaScript project for real-time event listening using Ethers.js and Node.js runtime. This project provides high-performance event listening capabilities for ERC20 tokens and Uniswap V2/V3 pools.

Features

• Real-time event monitoring using WebSocket connections
• Support for multiple contract types:
  • ERC20 Tokens (Transfer, Approval events)
  • Uniswap V2 Pools (Swap, Sync, Mint, Burn events)
  • Uniswap V3 Pools (Swap, Flash, Mint, Burn, Collect events)
• Contract interactions using Ethers.js
• High-performance execution with Node.js runtime
• Configurable through environment variables

Prerequisites

• Node.js 21.x or higher
• An Ethereum WebSocket provider URL

Tech Stack

• Runtime: Node.js - v21.x or higher - JavaScript runtime
• Ethereum Client: Ethers.js v6.13.5 - Ethereum Client interactions
• Smart Contract Standards:
  • @openzeppelin/contracts v5.2.0
  • @uniswap/v2-core v1.0.1
  • @uniswap/v3-core v1.0.1
  • dotenv v16.4.7

Installation

1. Clone the repository:

git clone https://github.com/horizon-eth/continuous-event-listener-nodejs-ethersjs.git
cd continuous-event-listener-nodejs-ethersjs

2. Install dependencies:

npm install

3. Create a .env file based on example.env:

cp example.env .env

4. Configure your environment variables in .env:

PROVIDER_WSS_URL="your_websocket_provider_url"
TYPE="TOKEN"  # or "UNISWAPV2" or "UNISWAPV3"
ADDRESS="your_contract_address"
EVENT_NAME="Transfer"  # or other supported events

Usage

Start the event listener:

npm start

Supported Event Types

ERC20 Token Events

• Transfer
• Approval

Uniswap V2 Pool Events

• Swap
• Sync
• Mint
• Burn

Uniswap V3 Pool Events

• Swap
• Flash
• Mint
• Burn
• Collect
• IncreaseObservationCardinalityNext
• SetFeeProtocol
• CollectProtocol

Configuration

The project uses environment variables for configuration. See example.env for all available options:

• PROVIDER_WSS_URL: WebSocket provider URL for Ethereum network
• TYPE: Contract type ("TOKEN", "UNISWAPV2", or "UNISWAPV3")
• ADDRESS: Contract address to monitor
• EVENT_NAME: Event name to listen for

Performance Optimization

For optimal event listening performance:

1. Use a reliable WebSocket provider
2. Adjust polling intervals and other settings based on your needs:

   export const provider_wss_config = {
     staticNetwork: ethers.Network.from(CHAIN_ID),
     // polling: true,
     // pollingInterval: 1000,
   };

Development

The project uses JavaScript in the codebase. Key files:

• index.js: Application entrypoint
• src/callback/callback.js: Event processing logic
• src/config/config.js: Application Configs
• src/listener/listener.js: Event listening & reconnection logic
• src/utils/utils.js: Utility functions

Contributing

1. Fork the repository
2. Create your feature branch
3. Commit your changes
4. Push to the branch
5. Create a new Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.