第11章Webアプリケーション開発

$ npx create-react-app ethreact

$ npm install bootstrap@4.6.0 reactstrap@8.9.0 --legacy-peer-deps
$ npm install react-bootstrap
$ npm install web3@1.2.2

import React from 'react';
import ReactDOM from 'react-dom';
import 'bootstrap/dist/css/bootstrap.css';
import './index.css';
import App from './App';
import reportWebVitals from './reportWebVitals';

ReactDOM.render(
  <React.StrictMode>     <App />   </React.StrictMode>,
  document.getElementById('root')
);

// If you want to start measuring performance in your app, pass a function
// to log results (for example: reportWebVitals(console.log))
// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
reportWebVitals();

$ npm install -g truffle@5.0.2

$ truffle init

pragma solidity ^0.5.0;
contract TodoList {
  uint public taskCount = 0;

  struct Task {
    uint id;
    string content;
    bool completed;
  }

  mapping(uint => Task) public tasks;

  event TaskCreated(
    uint id,
    string content,
    bool completed
  );

  event TaskCompleted(
    uint id,
    bool completed
  );

  constructor () public {
    createTask("Check out dappuniversity.com");
  }

  function createTask(string memory _content) public {
    taskCount ++;
    tasks[taskCount] = Task(taskCount, _content, false);
    emit TaskCreated(taskCount, _content, false);
  }
  function toggleCompleted(uint _id) public {
    Task memory _task = tasks[_id];
    _task.completed = !_task.completed;
    tasks[_id] = _task;
    emit TaskCompleted(_id, _task.completed);
  }

}

$ truffle compile

> Compiled successfully using:
  - solc: 0.5.16+commit.9c3226ce.Emscription.clang

development: {
  host: "127.0.0.1",     // Localhost (default: none)
  port: 7545,            // Standard Ethereum port (default: none)
  network_id: "*",       // Any network (default: none)
},

// Configure your compilers
compilers: {
  solc: {
    // version: "0.5.1",    // Fetch exact version from solc-bin (default: truffle's version)
    // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
    // settings: {          // See the solidity docs for advice about optimization and evmVersion
     optimizer: {
       enabled: true,
       runs: 200
     },
    //  evmVersion: "byzantium"
    // }
  }
},

var TodoList = artifacts.require("./TodoList.sol");

module.exports = function(deployer) {
  deployer.deploy(TodoList);
};

$ truffle migrate