依赖和scripts

{
  "name": "hardhat-fund-me-fcc",
  "devDependencies": {
    "@nomiclabs/hardhat-ethers": "npm:hardhat-deploy-ethers@^0.3.0-beta.13",
    "@nomiclabs/hardhat-etherscan": "^3.0.0",
    "@nomiclabs/hardhat-waffle": "^2.0.2",
    "chai": "^4.3.4",
    "ethereum-waffle": "^3.4.0",
    "ethers": "^5.5.3",
    "hardhat": "^2.8.3",
    "hardhat-deploy": "^0.9.29",
    "hardhat-gas-reporter": "^1.0.7",
    "solidity-coverage": "^0.7.18",
    "@chainlink/contracts": "^0.3.1",
    "dotenv": "^14.2.0",
    "prettier-plugin-solidity": "^1.0.0-beta.19"
  },
  "scripts": {
    "test": "hardhat test",
    "test:staging": "hardhat test --network goerli",
    "lint": "solhint 'contracts/*.sol'",
    "lint:fix": "solhint 'contracts/**/*.sol' --fix",
    "format": "prettier --write .",
    "coverage": "hardhat coverage"
  }
}

编写library库（工具类）PriceConverter

将第三方的.sol引入进来

yarn add @chainlink/contracts

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

library PriceConverter {
  function getPrice(AggregatorV3Interface priceFeed)
    internal
    view
    returns (uint256)
  {
    (, int256 answer, , , ) = priceFeed.latestRoundData();
    // ETH/USD rate in 18 digit
    return uint256(answer * 10000000000);
  }

  // 1000000000
  // call it get fiatConversionRate, since it assumes something about decimals
  // It wouldn't work for every aggregator
  function getConversionRate(uint256 ethAmount, AggregatorV3Interface priceFeed)
    internal
    view
    returns (uint256)
  {
    uint256 ethPrice = getPrice(priceFeed);
    uint256 ethAmountInUsd = (ethPrice * ethAmount) / 1000000000000000000;
    // the actual ETH/USD conversation rate, after adjusting the extra 0s.
    return ethAmountInUsd;
  }
}

hardhat提供了很多我们在使用ethers.js时很难实现的工具或者快捷的方法

搭建项目

yarn hardhat

根据提示生成一个简单的框架模版 例如这样：

添加需要的依赖

{
  "name": "hardhat-simple-storage-fcc",
  "author": "maochaoying",
  "devDependencies": {
    "@nomiclabs/hardhat-ethers": "^2.0.4",
    "@nomiclabs/hardhat-etherscan": "^3.0.0",
    "@nomiclabs/hardhat-waffle": "^2.0.2",
    "chai": "^4.3.4",
    "ethereum-waffle": "^3.4.0",
    "ethers": "^5.5.3",
    "hardhat": "^2.8.3",
    "hardhat-gas-reporter": "^1.0.7",
    "solidity-coverage": "^0.7.18"
  },
  "dependencies": {
    "dotenv": "^14.2.0",
    "prettier-plugin-solidity": "^1.0.0-beta.19"
  },
  "scripts": {
    "lint": "yarn prettier --check .",
    "lint:fix": "yarn prettier --write ."
  }
}

solidity-coverage

hardhat提供了一个查看当前我们编写的测试代码的功能覆盖率的插件，叫做solidity-coverage，专门用于可靠性测试的代码覆盖率。

创建项目

yarn hardhat

部署

const { ethers } = require("hardhat");

async function main() {
  const contractFactory = await ethers.getContractFactory("SimpleStorage");
  const contract = await contractFactory.deploy();
  console.log(contract.address);
  await contract.deployed();
}

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

依赖项

package.json

{
  "dependencies": {
    "dotenv": "^16.0.3",
    "ethers": "^5.7.1",
    "fs-extra": "^10.1.0",
    "prettier": "^2.7.1",
    "prettier-plugin-solidity": "^1.0.0-beta.24",
    "solc": "0.8.7-fixed"
  },
  "scripts": {
    "compile": "yarn solcjs --bin --abi --include-path node_modules/ --base-path . -o . SimpleStorage.sol"
  }
}

搭建本地 Ethereum blockchain

官网：ganache

Quickly fire up a personal Ethereum blockchain which you can use to run tests, execute commands, and inspect state while controlling how the chain operates.

ethers.js

官网： https://learnblockchain.cn/docs/ethers.js/

ethers.js 库是为以太坊 提供的一个的小而完整的 JavaScript 库。

安装ethers

npm install --save ethers

导入ethers

const ethers = require('ethers');

下载vscode

官网：https://code.visualstudio.com/

安装插件

solidity + hardhat

地址：Solidity