hardhat-observer

Realtime event monitor and transaction logger for Hardhat projects.

Designed to simplify debugging, monitoring and observability during smart contract development.

Features

• Realtime contract event monitoring
• Automatic ABI decoding
• Multi-contract support
• Transaction event inspection
• Automatic contract registration via ENV
• Generic event rendering
• Compatible with ethers v5
• Works with local Hardhat node

Installation

npm install

or

yarn

Start Hardhat Node

npx hardhat node

Deploy Contracts

Example:

npx hardhat run scripts/deploy.js --network localhost

Environment Convention

The monitor automatically discovers contracts using ENV variables.

Example:

ADDR_LG_USDT=0x...
ABI_LG_USDT=MockERC20

ADDR_LG_DAI=0x...
ABI_LG_DAI=MockERC20

ADDR_LG_MOCK_DEX=0x...
ABI_LG_MOCK_DEX=MockDex

Realtime Monitor

npx hardhat run backend/logs.js --network localhost

Example:

============================================================
[USDT] Transfer
------------------------------------------------------------
from: 0x0000000000000000000000000000000000000000
to:   0x70997970C51812dc3A010C7d01b50e0d17dc79C8
value: 1000000000

Basic Usage

Create Monitor

const hre = require("hardhat");

const {
    EventMonitor
} = require("./lib/event-monitor");

const monitor =
    new EventMonitor(hre);

Automatic Registration

await monitor.autoRegister();

Start Monitor

monitor.start();

Manual Registration

monitor.register("USDT", usdt);

monitor.register("DAI", dai);

monitor.register("MOCK_DEX", mockDex);

Transaction Inspection

Useful for scripts, deploys and tests.

const tx = await contract.transfer(...);

await monitor.inspectTx(tx);

Example Architecture

/scripts
    deploy.js
    tests.js

/backend
    logs.js

/lib
    event-monitor.js

Recommended Workflow

Terminal 1

Run Hardhat node:

npx hardhat node

Terminal 2

Run monitor:

npx hardhat run backend/logs.js --network localhost

Terminal 3

Execute tests/scripts:

npx hardhat run scripts/teste.js --network localhost

Supported Event Types

The monitor is ABI-based and works with any contract event.

Examples:

• ERC20 Transfer
• ERC20 Approval
• Custom DEX events
• Lending protocol events
• Generic EVM logs

Current Goals

• Simple
• Generic
• Reusable
• Hardhat-first
• Low configuration
• Fast debugging

Future Improvements

• Transaction grouping
• Address aliases
• Colored logs
• Token metadata formatting
• Event filtering
• File persistence
• Trace support
• Gas metrics
• Multi-network support

License

MIT