3. 使用 Hardhat

使用 Hardhat 在 ChainIDE 上快速搭建一个 dApp。

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3. 使用 Hardhat

使用 Hardhat 在 ChainIDE 上快速搭建一个 dApp。

1. 打开 Sandbox

注：以 GIthub 方式登录 ChainIDE 后才可使用 Sandbox 功能。

打开 Sandbox

2. 快速开始

我们将探索使用示例合约创建 Hardhat 项目的基础知识、该合约的测试以及部署它的脚本。

要创建示例项目，请在项目文件夹中运行 npx hardhat init ：

$ npx hardhat init
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888    888 "Y888888 888     "Y88888 888  888 "Y888888  "Y888

👷 Welcome to Hardhat v2.19.1 👷‍

? What do you want to do? …
❯ Create a JavaScript project
  Create a TypeScript project
  Create an empty hardhat.config.js
  Quit

3. 运行任务

要首先快速了解可用的内容和正在发生的情况，请在项目文件夹中运行 npx hardhat ：

$ npx hardhat
Hardhat version 2.9.9

Usage: hardhat [GLOBAL OPTIONS] <TASK> [TASK OPTIONS]

GLOBAL OPTIONS:

  --config              A Hardhat config file.
  --emoji               Use emoji in messages.
  --help                Shows this message, or a task's help if its name is provided
  --max-memory          The maximum amount of memory that Hardhat can use.
  --network             The network to connect to.
  --show-stack-traces   Show stack traces.
  --tsconfig            A TypeScript config file.
  --verbose             Enables Hardhat verbose logging
  --version             Shows hardhat's version.


AVAILABLE TASKS:

  check                 Check whatever you need
  clean                 Clears the cache and deletes all artifacts
  compile               Compiles the entire project, building all artifacts
  console               Opens a hardhat console
  coverage              Generates a code coverage report for tests
  flatten               Flattens and prints contracts and their dependencies
  help                  Prints this message
  node                  Starts a JSON-RPC server on top of Hardhat Network
  run                   Runs a user-defined script after compiling the project
  test                  Runs mocha tests
  typechain             Generate Typechain typings for compiled contracts
  verify                Verifies contract on Etherscan

To get help for a specific task run: npx hardhat help [task]

可用任务列表包括内置任务以及任何已安装插件附带的任务。 npx hardhat 是您了解哪些任务可以运行的起点。

4. 编译你的合约

接下来，如果您查看 contracts/ 文件夹，您将看到 Lock.sol ：

// 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);
    }
}

要编译它，只需运行：

npx hardhat compile

如果您创建了 TypeScript 项目，此任务还将使用 TypeChain 生成 TypeScript 绑定。

5. 测试你的合约

您的项目附带使用 Mocha、Chai 和 Ethers.js 的测试。

如果您查看 test/ 文件夹，您将看到一个测试文件：

import {
  time,
  loadFixture,
} from "@nomicfoundation/hardhat-toolbox/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.target)).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]
        );
      });
    });
  });
});

您可以使用 npx hardhat test 运行测试：

$ npx hardhat test
Generating typings for: 2 artifacts in dir: typechain-types for target: ethers-v6
Successfully generated 6 typings!
Compiled 2 Solidity files successfully


  Lock
    Deployment
      ✔ Should set the right unlockTime (610ms)
      ✔ Should set the right owner
      ✔ Should receive and store the funds to lock
      ✔ Should fail if the unlockTime is not in the future
    Withdrawals
      Validations
        ✔ Should revert with the right error if called too soon
        ✔ Should revert with the right error if called from another account
        ✔ Shouldn't fail if the unlockTime has arrived and the owner calls it
      Events
        ✔ Should emit an event on withdrawals
      Transfers
        ✔ Should transfer the funds to the owner


  9 passing (790ms)

6. 部署你的合约

接下来，为了部署合约，我们将使用 Hardhat 脚本。

在 scripts/ 文件夹中，您将找到一个包含以下代码的文件：

import { ethers } from "hardhat";

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

  const lockedAmount = ethers.parseEther("0.001");

  const lock = await ethers.deployContract("Lock", [unlockTime], {
    value: lockedAmount,
  });

  await lock.waitForDeployment();

  console.log(
    `Lock with ${ethers.formatEther(
      lockedAmount
    )}ETH and unlock timestamp ${unlockTime} deployed to ${lock.target}`
  );
}

// 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;
});

您可以使用 npx hardhat run scripts/deploy.ts 运行它：

$ npx hardhat run scripts/deploy.ts
Lock with 1 ETH deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3

7. 将钱包或 Dapp 连接到 Hardhat 网络

默认情况下，Hardhat 将在启动时启动一个新的内存中 Hardhat 网络实例。还可以以独立方式运行 Hardhat Network，以便外部客户端可以连接到它。这可以是钱包、Dapp 前端或脚本。要以这种方式运行 Hardhat Network，请运行 npx hardhat node ：

$ npx hardhat node
Started HTTP and WebSocket JSON-RPC server at http://127.0.0.1:8545/

这将向 Hardhat 网络公开 JSON-RPC 接口。要使用它，请将您的钱包或应用程序连接到 http://127.0.0.1:8545 。

如果您想将 Hardhat 连接到此节点，例如要针对它运行部署脚本，您只需使用 --network localhost 运行它。

要尝试此操作，请使用 npx hardhat node 启动节点并使用 network 选项重新运行部署脚本：

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

恭喜！您已经创建了一个项目并编译、测试和部署了智能合约。

8. 继续学习