Hardhat is an Ethereum development environment that provides developers with various tools for building, testing, and debugging smart contracts. One of the essential features of Hardhat is the ability to view transaction details, which can help in understanding the behavior of your contracts and diagnosing issues. This guide will explain how to view transaction details in Hardhat, along with sample code and usage scenarios.

1. What Are Transaction Details?

Transaction details refer to the information related to a specific transaction executed on the Ethereum network. This includes data such as:

• Transaction Hash: A unique identifier for the transaction.
• Block Number: The block in which the transaction was included.
• From Address: The address that initiated the transaction.
• To Address: The address that received the transaction.
• Value: The amount of Ether transferred (if applicable).
• Gas Used: The amount of gas consumed by the transaction.
• Input Data: The data sent along with the transaction, typically in the form of function calls to smart contracts.

2. Viewing Transaction Details in Hardhat

To view transaction details in Hardhat, you can use several methods, including the Hardhat console, event logs, and transaction receipts. Below are examples of each method.

2.1. Using the Hardhat Console

When you run a transaction in the Hardhat console, you can capture the transaction receipt, which contains the transaction details. Here’s how to do it:

npx hardhat console --network localhost

Once in the console, you can interact with your deployed contract. For example, consider you have a simple ERC20 token contract:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract MyToken {
    string public name = "MyToken";
    mapping(address => uint256) public balances;

    function mint(address to, uint256 amount) public {
        balances[to] += amount;
    }

    function balanceOf(address account) public view returns (uint256) {
        return balances[account];
    }
}

Assuming you have deployed the contract, you can mint tokens and view the transaction details:

const MyToken = await ethers.getContractFactory("MyToken");
const myToken = await MyToken.attach("DEPLOYED_CONTRACT_ADDRESS"); // Replace with the actual address

// Mint tokens and capture the transaction response
const txResponse = await myToken.mint("ADDRESS_TO_RECEIVE_TOKENS", 100);
console.log("Transaction Response:", txResponse);

// Wait for the transaction to be mined
const txReceipt = await txResponse.wait();
console.log("Transaction Receipt:", txReceipt);

In this example:

• You mint tokens to a specified address and capture the transaction response.
• You then wait for the transaction to be mined and capture the transaction receipt.
• The transaction receipt contains detailed information about the transaction.

2.2. Examining the Transaction Receipt

The transaction receipt contains various details that you can log to the console:

console.log("Transaction Hash:", txReceipt.transactionHash);
console.log("Block Number:", txReceipt.blockNumber);
console.log("From Address:", txReceipt.from);
console.log("To Address:", txReceipt.to);
console.log("Gas Used:", txReceipt.gasUsed.toString());
console.log("Status:", txReceipt.status ? "Success" : "Failed");

By logging these details, you can get a comprehensive view of the transaction and its outcome.

2.3. Using Event Logs

Another way to view transaction details is by using event logs emitted by your smart contracts. Events are a way to log information on the blockchain that can be easily accessed later.

For example, you can modify the mint function to emit an event:

event TokensMinted(address indexed to, uint256 amount);

function mint(address to, uint256 amount) public {
    balances[to] += amount;
    emit TokensMinted(to, amount);
}

After minting tokens, you can listen for the event in the console:

const filter = myToken.filters.TokensMinted("ADDRESS_TO_RECEIVE_TOKENS", null);
const events = await myToken.queryFilter(filter);
console.log("Minted Events:", events);

This code snippet sets up a filter for the TokensMinted event and retrieves the events related to the specified address. The output will provide details about the minting transactions, including the addresses and amounts involved.

3. Conclusion

Viewing transaction details in Hardhat is crucial for debugging and understanding the behavior of your smart contracts. By utilizing the Hardhat console, examining transaction receipts, and leveraging event logs, you can gain valuable insights into your transactions. This knowledge is essential for developing robust and efficient Ethereum applications.