hardhat

Compiling Smart Contracts

Hardhat can compile your smart contracts using the Solidity compiler. You can specify the version of Solidity you want to use in the configuration file.

module.exports = {
  solidity: "0.8.4",
};

Running Tests

Hardhat allows you to write tests for your smart contracts using popular testing frameworks like Mocha and Chai. This example shows a simple test for a token contract.

const { expect } = require("chai");

describe("Token contract", function () {
  it("Deployment should assign the total supply of tokens to the owner", async function () {
    const [owner] = await ethers.getSigners();
    const Token = await ethers.getContractFactory("Token");
    const hardhatToken = await Token.deploy();
    const ownerBalance = await hardhatToken.balanceOf(owner.address);
    expect(await hardhatToken.totalSupply()).to.equal(ownerBalance);
  });
});

Deploying Contracts

Hardhat makes it easy to deploy your smart contracts to the Ethereum network. This script deploys a token contract and logs the address to which it was deployed.

async function main() {
  const [deployer] = await ethers.getSigners();
  console.log("Deploying contracts with the account:", deployer.address);
  const Token = await ethers.getContractFactory("Token");
  const token = await Token.deploy();
  console.log("Token deployed to:", token.address);
}

main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

Debugging

Hardhat provides a powerful debugging tool that allows you to inspect the state of your contracts at any point in time. This example shows a custom task that prints the list of accounts.

const { task } = require("hardhat/config");

task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
  const accounts = await hre.ethers.getSigners();
  for (const account of accounts) {
    console.log(account.address);
  }
});