Getting Started with Hardhat on INK

This guide will walk you through setting up a new project using Hardhat, a popular development environment for Ethereum software.

Prerequisites

First, make sure you have Node.js installed (version 20 or later). You can check your Node version with:

node --version

Setting Up a New Hardhat Project

Create a new directory for your project and initialize it:

mkdir my-hardhat-project
cd my-hardhat-project
npm init -y

Install Hardhat and necessary dependencies:

npm install --save-dev hardhat @nomicfoundation/hardhat-toolbox

Create a new Hardhat project:

npx hardhat init

Choose "Create a JavaScript project" when prompted. This will create a project with this structure:

my-hardhat-project/
├── contracts/
├── scripts/
├── test/
├── hardhat.config.js
└── package.json

Writing Your First Contract

Create a new file in the contracts directory:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
 
contract InkContract {
    string public greeting = "Hello, Ink!";
    
    function setGreeting(string memory _greeting) public {
        greeting = _greeting;
    }
}

Configuring Hardhat

Create a .env file in your project root:

PRIVATE_KEY=your_private_key_here
INK_SEPOLIA_URL=https://rpc-gel-sepolia.inkonchain.com/
BLOCKSCOUT_API_KEY=your_blockscout_api_key_here

Update your hardhat.config.js:

require("@nomicfoundation/hardhat-toolbox");
require("dotenv").config();
 
/** @type import('hardhat/config').HardhatUserConfig */
module.exports = {
  solidity: "0.8.19",
  networks: {
    inksepolia: {
      url: process.env.INK_SEPOLIA_URL || "",
      accounts: process.env.PRIVATE_KEY ? [process.env.PRIVATE_KEY] : [],
    },
  },
  etherscan: {
    apiKey: {
      inksepolia: process.env.BLOCKSCOUT_API_KEY,
    },
    customChains: [
      {
        network: "inksepolia",
        chainId: 763373,
        urls: {
          apiURL: "https://explorer-sepolia.inkonchain.com/api/v2",
          browserURL: "https://explorer-sepolia.inkonchain.com/",
        },
      },
    ],
  },
};

Building and Testing

Compile your contracts:

npx hardhat compile

Create a test file in test/InkContract.js:

const { expect } = require("chai");
 
describe("InkContract", function () {
  it("Should return the correct greeting", async function () {
    const InkContract = await ethers.getContractFactory("InkContract");
    const contract = await InkContract.deploy();
    await contract.deployed();
 
    expect(await contract.greeting()).to.equal("Hello, Ink!");
  });
});

Run the tests:

npx hardhat test

Deployment

Create a deployment script in scripts/deploy.js:

async function main() {
  const InkContract = await ethers.getContractFactory("InkContract");
  const contract = await InkContract.deploy();
 
  await contract.deployed();
 
  console.log("InkContract deployed to:", contract.address);
}
 
main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

Deploy to INK Sepolia testnet:

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

Verifying Your Contract

After deployment, verify your contract:

npx hardhat verify --network inksepolia <DEPLOYED_CONTRACT_ADDRESS>

Interacting with Your Contract

You can use Hardhat Console to interact with your deployed contract:

npx hardhat console --network inksepolia

const Contract = await ethers.getContractFactory("InkContract");
const contract = await Contract.attach("YOUR_CONTRACT_ADDRESS");
await contract.greeting();
await contract.setGreeting("New greeting!");

Additional Tools

Hardhat comes with several built-in tools:

Hardhat Network: Local Ethereum network for development
Console: Interactive JavaScript environment
Gas Reporter: Gas usage reporting
Coverage: Code coverage for Solidity tests

To use the network for local development:

npx hardhat node

Next Steps

Explore Hardhat Documentation for more features

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