HardHat: 導入方法

Hardhat

EVM（Ethereum Virtual Machine）に対応したスマートコントラクトの開発環境ツールです。

公式：https://hardhat.org/

Hardhatの特徴

• プラグインで拡張が可能
• TypeScript対応
• solidityファイル内でconsole.log()が使用可能

Hardhatの導入方法

インストール

空のフォルダを作成して、Hardhatのインストールを行います。

# フォルダを作成
mkdir project

# フォルダに移動
cd project

# npmプロジェクトを作成
npm initoryarn init

# hardhatをインストール
npm install --save-dev hardhat
or
yarn add --dev hardhat

クイックスタート

# サンプルプロジェクトを作成
npx hardhat

以下が出力されるので、「Create a TypeScript project」を選択します。

$ npx hardhat
888    888                      888 888               888
888    888                      888 888               888
888    888                      888 888               888
8888888888  8888b.  888d888 .d88888 88888b.   8888b.  888888
888    888     "88b 888P"  d88" 888 888 "88b     "88b 888
888    888 .d888888 888    888  888 888  888 .d888888 888
888    888 888  888 888    Y88b 888 888  888 888  888 Y88b.
888    888 "Y888888 888     "Y88888 888  888 "Y888888  "Y888

👷 Welcome to Hardhat v2.9.9 👷‍

? What do you want to do? …
❯ Create a JavaScript project: JavaScriptに対応したサンプルプロジェクトを作成
  Create a TypeScript project: TypeScriptに対応したサンプルプロジェクトを作成
  Create an empty hardhat.config.js: 設定ファイルのみを作成
  Quit: 終了

ディレクトリ構成

以下が初期状態の構成です。

project
 ├ contracts/ Solidityファイルを設置するディレクトリ
 │  └ Lock.sol
 ├ scripts/   デプロイなどのスクリプトファイルを設置するディレクトリ
 │  └ deploy.sol
 ├ test/      テストスクリプトを設置するディレクトリ
 │  └ Lock.ts
 ├ hardhat.config.ts hardhatの設定ファイル
 ├ package.json
 ├ README.md
 └ tsconfig.json

contracts/Lock.sol

コントラクトアドレス宛に送金したトークンが、設定時間を超えると回収できる機能を持ったコントラクトです。

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.9;

// Uncomment this line to use console.log
// import "hardhat/console.sol";

contract Lock {
    uint public unlockTime;
    address payable public owner;

    event Withdrawal(uint amount, uint when);

    constructor(uint _unlockTime) payable {
        require(
            block.timestamp < _unlockTime,
            "Unlock time should be in the future"
        );

        unlockTime = _unlockTime;
        owner = payable(msg.sender);
    }

    function withdraw() public {
        // Uncomment this line, and the import of "hardhat/console.sol", to print a log in your terminal
        // console.log("Unlock time is %o and block timestamp is %o", unlockTime, block.timestamp);

        require(block.timestamp >= unlockTime, "You can't withdraw yet");
        require(msg.sender == owner, "You aren't the owner");

        emit Withdrawal(address(this).balance, block.timestamp);

        owner.transfer(address(this).balance);
    }
}

scripts/deploy.ts

Lock Contractに引数を渡してデプロイするスクリプトです。

import { ethers } from "hardhat";

async function main() {
  const currentTimestampInSeconds = Math.round(Date.now() / 1000);
  const ONE_YEAR_IN_SECS = 365 * 24 * 60 * 60;
  const unlockTime = currentTimestampInSeconds + ONE_YEAR_IN_SECS;

  const lockedAmount = ethers.utils.parseEther("1");

  const Lock = await ethers.getContractFactory("Lock");
  const lock = await Lock.deploy(unlockTime, { value: lockedAmount });

  await lock.deployed();

  console.log(`Lock with 1 ETH and unlock timestamp ${unlockTime} deployed to ${lock.address}`);
}

// We recommend this pattern to be able to use async/await everywhere
// and properly handle errors.
main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

tests/Lock.ts

Lock Contractのテストコードです。

import { time, loadFixture } from "@nomicfoundation/hardhat-network-helpers";
import { anyValue } from "@nomicfoundation/hardhat-chai-matchers/withArgs";
import { expect } from "chai";
import { ethers } from "hardhat";

describe("Lock", function () {
  // We define a fixture to reuse the same setup in every test.
  // We use loadFixture to run this setup once, snapshot that state,
  // and reset Hardhat Network to that snapshot in every test.
  async function deployOneYearLockFixture() {
    const ONE_YEAR_IN_SECS = 365 * 24 * 60 * 60;
    const ONE_GWEI = 1_000_000_000;

    const lockedAmount = ONE_GWEI;
    const unlockTime = (await time.latest()) + ONE_YEAR_IN_SECS;

    // Contracts are deployed using the first signer/account by default
    const [owner, otherAccount] = await ethers.getSigners();

    const Lock = await ethers.getContractFactory("Lock");
    const lock = await Lock.deploy(unlockTime, { value: lockedAmount });

    return { lock, unlockTime, lockedAmount, owner, otherAccount };
  }

  describe("Deployment", function () {
    it("Should set the right unlockTime", async function () {
      const { lock, unlockTime } = await loadFixture(deployOneYearLockFixture);

      expect(await lock.unlockTime()).to.equal(unlockTime);
    });

    it("Should set the right owner", async function () {
      const { lock, owner } = await loadFixture(deployOneYearLockFixture);

      expect(await lock.owner()).to.equal(owner.address);
    });

    it("Should receive and store the funds to lock", async function () {
      const { lock, lockedAmount } = await loadFixture(
        deployOneYearLockFixture
      );

      expect(await ethers.provider.getBalance(lock.address)).to.equal(
        lockedAmount
      );
    });

    it("Should fail if the unlockTime is not in the future", async function () {
      // We don't use the fixture here because we want a different deployment
      const latestTime = await time.latest();
      const Lock = await ethers.getContractFactory("Lock");
      await expect(Lock.deploy(latestTime, { value: 1 })).to.be.revertedWith(
        "Unlock time should be in the future"
      );
    });
  });

  describe("Withdrawals", function () {
    describe("Validations", function () {
      it("Should revert with the right error if called too soon", async function () {
        const { lock } = await loadFixture(deployOneYearLockFixture);

        await expect(lock.withdraw()).to.be.revertedWith(
          "You can't withdraw yet"
        );
      });

      it("Should revert with the right error if called from another account", async function () {
        const { lock, unlockTime, otherAccount } = await loadFixture(
          deployOneYearLockFixture
        );

        // We can increase the time in Hardhat Network
        await time.increaseTo(unlockTime);

        // We use lock.connect() to send a transaction from another account
        await expect(lock.connect(otherAccount).withdraw()).to.be.revertedWith(
          "You aren't the owner"
        );
      });

      it("Shouldn't fail if the unlockTime has arrived and the owner calls it", async function () {
        const { lock, unlockTime } = await loadFixture(
          deployOneYearLockFixture
        );

        // Transactions are sent using the first signer by default
        await time.increaseTo(unlockTime);

        await expect(lock.withdraw()).not.to.be.reverted;
      });
    });

    describe("Events", function () {
      it("Should emit an event on withdrawals", async function () {
        const { lock, unlockTime, lockedAmount } = await loadFixture(
          deployOneYearLockFixture
        );

        await time.increaseTo(unlockTime);

        await expect(lock.withdraw())
          .to.emit(lock, "Withdrawal")
          .withArgs(lockedAmount, anyValue); // We accept any value as `when` arg
      });
    });

    describe("Transfers", function () {
      it("Should transfer the funds to the owner", async function () {
        const { lock, unlockTime, lockedAmount, owner } = await loadFixture(
          deployOneYearLockFixture
        );

        await time.increaseTo(unlockTime);

        await expect(lock.withdraw()).to.changeEtherBalances(
          [owner, lock],
          [lockedAmount, -lockedAmount]
        );
      });
    });
  });
});

動作確認

# コンパイル
npx hardhat compile

# テスト
npx hardhat test

# Nodeサーバー起動
npx hardhat node

# 起動したNodeサーバー上にデプロイ
npx hardhat run scripts/deploy.ts --network localhost

まとめ

Hardhatの導入方法をまとめてみました。

プラグイン導入で拡張性があり、デバッグもできるので非常に便利なツールです。