web3

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web3

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工具:

• 在线IDE remix
• Solidity官方文档
• hardhat ** 合约开发框架
• openzeppelin-contracts 必备智能合约库
• ethers.js ** 更好
• web3.js

Web3 hooks

• wagmi **
  react hooks

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教程:

• https://www.learnweb3.io
• https://deschool.app/landing
• https://github.com/dukedaily/solidity-expert
• https://eattheblocks.com/
• https://ethernaut.openzeppelin.com/
  和安全有关的教程
• https://solidity-by-example.org/
  solidity 案例，用于学习一些 solidity 用法
• https://ethereum.org/zh/developers/docs/
  官方文档

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节点:

• alchemyapi
• infura

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Vue web3

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获取账户历史 eth balance

web3js 方案

let blockNum = web3.eth.blockNumber;
const historicTimestamp = new Date(historicDate).getTime();
while(true) {
  const block = web3.eth.getBlock(blockNum);
  if(block.timestamp < historicTimestamp) break;
  --blockNum;
}

//The blockNumber here is your required block number
web3.eth.getBalance(address, blockNumber).then(balance => `Balance at block number is ${balance}`);

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资料

• https://github.com/Dapp-Learning-DAO/Dapp-Learning
• 代码库：https://www.cookbook.dev/

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合约

• 安全相关合约 https://github.com/safe-global/safe-contracts

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ERC20

• base contract: import '@openzeppelin/contracts/token/ERC20/ERC20.sol';
• 基础合约数据
  • mapping(address => uint256) private _balances; 余额，记录每个地址有多少 token
  • mapping(address => mapping(address => uint256)) private _allowances 授权委托记录，记录 approve 信息
  • uint256 private _totalSupply 总供应量
  • _name, _symbol 合约名称，合约缩写

固定供应量并全解锁合约

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

import '@openzeppelin/contracts/token/ERC20/ERC20.sol';

/**
 * 合约创建初始化总供应量并且全部解锁
 */
contract OneToken is ERC20 {
  string constant TOKEN_NAME = 'OneToken';
  string constant TOKEN_SYMBOL = 'OTK';

  constructor(uint256 initialSupply) ERC20(TOKEN_NAME, TOKEN_SYMBOL) {
    _mint(msg.sender, initialSupply);
  }
}

每年增发 20%

参考: ENS

contract OneToken is ERC20, Ownable {
  string constant TOKEN_NAME = 'OneToken';
  string constant TOKEN_SYMBOL = 'OTK';

  uint256 public constant minimumMintInterval = 365 days;
  uint256 public constant mintCap = 200; // 2%

  uint256 public nextMint; // Timestamp

  constructor(uint256 initialSupply) ERC20(TOKEN_NAME, TOKEN_SYMBOL) {
    _mint(msg.sender, initialSupply);

    nextMint = block.timestamp + minimumMintInterval;
  }

  function mint(address dest, uint256 amount) external onlyOwner {
    require(amount < (totalSupply() * mintCap) / 10000, 'OTK: Mint exceeds maximum amount');
    require(block.timestamp >= nextMint, 'OTK: Cannot mint yet');

    nextMint = block.timestamp + minimumMintInterval;
    _mint(dest, amount);
  }
}

Burnable

默认不支持销毁

import '@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol';

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solidity tips

1. address(0): 0 地址，用于销毁 token

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mocha, chai

• 执行某个交易后判断余额

await expect(() => oneToken.transfer(otherAccount, 1)).to.changeTokenBalance(oneToken, owner, '-1')

• 报错检查

      await expect(oneToken.connect(otherAccount).mint(owner.address, 1000)).to.be.revertedWith(
        'Ownable: caller is not the owner'
      )

await expect(oneToken.mint(owner.address, 1000)).to.be.revertedWith('OTK: Cannot mint yet')

• 不报错测试

await expect(oneToken.mint(owner.address, 1000)).not.to.be.reverted

• 时间测试，修改时间

      const unlockTime = (await time.latest()) + ONE_YEAR_IN_SECS
      // We can increase the time in Hardhat Network
      await time.increaseTo(unlockTime)