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1. 🔥React入门与概览（JSX语法）
2. 🔥面向组件编程——组件实例的三大核心属性state、props和refs超详解
3. 🔥受控组件与非受控组件（vue和react的双向绑定分别是怎么实现的？）
4. 🔥React函数的柯里化（什么？这玩意儿不仅能装x，还能优化代码？）
5. 🔥四行代码让我的cpu跑上90度——走进组件生命周期
6. 🔥图文详解react组件生命周期——React v16.8
7. 🔥react新生命周期图文详解——最新版
8. 🔥react-getSnapshotBeforeUpdate()生命周期函数详解
9. 🔥使用create-react-app（CRA）创建react项目
10. 🔥react父子组件传值（通信）
11. 🔥拆分组件思想-吃饭、睡觉、打代码案例（附源码）（👈本文）

---

本例使用的是React v18.1技术栈

🏆组件的组合使用-TodoList

功能: 组件化实现此功能

1.显示所有todo列表

2.输入文本,点击按钮显示到列表的首位,并清除输入的文本

▶️拆分组件

📎项目结构

📌index.js

import React from 'react';
import ReactDOM from 'react-dom/client';
import App from './App';

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

📌App.jsx

import React, { Component } from 'react';
import Header from './components/Header';
import List from './components/List';
import Footer from './components/Footer';
import './App.css'

class App extends Component {
  // 状态在哪里，操作状态的方法就在哪里

  state = {
    todos: [
      { id: '001', name: '吃饭', done: true },
      { id: '002', name: '睡觉', done: true },
      { id: '003', name: '打代码', done: false },
      { id: '004', name: '逛街', done: true }
    ]
  }

  // addTodo用于添加一个todo，接受的参数是todo对象
  addTodo = (todoObj) => {
    const { todos } = this.state
    const newTodos = [todoObj, ...todos]
    this.setState({ todos: newTodos });
  }

  // 用于勾选和取消勾选todo
  updateTodo = (id, done) => {
    // 获取todos
    const { todos } = this.state
    // 匹配处理数据
    const newTodos = todos.map((todoObj) => {
      if (todoObj.id === id) return { ...todoObj, done }
      else return todoObj
    })
    this.setState({ todos: newTodos });
  }

  // 用于删除一个todo
  deleteTodo = (id) => {
    const { todos } = this.state
    // 删除指定ID的todo对象
    const newTodos = todos.filter((todoObj) => {
      // 数组的过滤方法，返回id不等于传进来的id值的那些todoObj对象，说明排除掉了点击了删除id对应的那个todoObj
      return todoObj.id !== id
    })
    this.setState({ todos: newTodos });
  }

  // 用于全选
  checkAllTodo = (done) => {
    const { todos } = this.state
    const newTodos = todos.map((todoObj) => {
      return { ...todoObj, done }
    })
    this.setState({ todos: newTodos });
  }

  // 用于清除已完成任务
  clearAllDone = () => {
    const { todos } = this.state
    // 过滤数据
    const newTodos = todos.filter((todoObj) => {
      return todoObj.done !== true
    })
    this.setState({ todos: newTodos });
  }


  render() {
    return (
      <div className="todo-container">
        <div className="todo-wrap">
          <Header addTodo={this.addTodo} />
          <List todos={this.state.todos} 
          		updateTodo={this.updateTodo} 
          		deleteTodo={this.deleteTodo} />
          <Footer todos={this.state.todos} 
          		  checkAllTodo={this.checkAllTodo} 
          		  clearAllDone={this.clearAllDone} />
        </div>
      </div>
    );
  }
}
export default App;

📌App.css

/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}

.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}

---

Header部分

🛠Header-index.jsx

import React, { Component } from 'react';
import PropTypes from 'prop-types';
import { nanoid } from 'nanoid'
import './index.css'

class Header extends Component {

  // 键盘事件的回调
  handleKeyUp = (event) => {
    if (event.key !== 'Enter') return
    console.log(event.target.value, event.keyCode, event.key)
    // 添加的todo名字不能为空
    if (event.target.value.trim() === '') {
      alert('输入不能为空')
      return
    }
    const todoObj = { id: nanoid(), name: event.target.value, done: false }
    this.props.addTodo(todoObj)

    // 清空输入框
    event.target.value = ''
  }

  // 对接收的props进行类型限制
  static propTypes = {
    addTodo: PropTypes.func.isRequired,
  }

  render() {
    return (
      <div className="todo-header">
        <input onKeyUp={this.handleKeyUp} type="text" placeholder="请输入你的任务名称，按回车键确认" />
      </div>
    );
  }
}

export default Header;

🛠Header-index.css

/*header*/
.todo-header input {
  width: 560px;
  height: 28px;
  font-size: 14px;
  border: 1px solid #ccc;
  border-radius: 4px;
  padding: 4px 7px;
}

.todo-header input:focus {
  outline: none;
  border-color: rgba(82, 168, 236, 0.8);
  box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(82, 168, 236, 0.6);
}

---

List部分

🛠List-index.jsx

import React, { Component } from 'react';
import PropTypes from 'prop-types';
import Item from '../Item';
import './index.css'

class List extends Component {

  // 对接收的props进行类型限制
  static propTypes = {
    todos: PropTypes.array.isRequired,
    updateTodo: PropTypes.func.isRequired,
    deleteTodo: PropTypes.func.isRequired,
  }

  render() {
    const { todos, updateTodo, deleteTodo } = this.props
    return (
      <ul className="todo-main">
        {
          todos.map(todo => {
            return <Item key={todo.id} {...todo} 
            			updateTodo={updateTodo} 
            			deleteTodo={deleteTodo} />
          })
        }
      </ul>
    );
  }
}
export default List;

🛠List-index.css

/*main*/
.todo-main {
  margin-left: 0px;
  border: 1px solid #ddd;
  border-radius: 2px;
  padding: 0px;
}

.todo-empty {
  height: 40px;
  line-height: 40px;
  border: 1px solid #ddd;
  border-radius: 2px;
  padding-left: 5px;
  margin-top: 10px;
}

---

Item部分

🛠Item-index.jsx

import React, { Component } from 'react';
import './index.css'

class Item extends Component {

  // 标识鼠标移入、移出
  state = { mouse: false }

  // 鼠标移入移出的回调
  handleMouse = (flag) => {
    return () => {
      this.setState({ mouse: flag });
    }
  }

  // checkbox勾选的回调
  handleCheck = (id) => {
    return (event) => {
      console.log(id, event.target.checked)
      this.props.updateTodo(id, event.target.checked)
    }
  }

  // 删除一个todo的回调
  handleDelete = (id, name) => {
    return () => {
      if (window.confirm('确定删除' + name + '吗？')) {
        this.props.deleteTodo(id)
      }
    }
  }

  render() {
    const { id, name, done } = this.props
    return (
      <li style={{ backgroundColor: this.state.mouse ? '#ddd' : 'white' }} 
      	  onMouseEnter={this.handleMouse(true)} 
          onMouseLeave={this.handleMouse(false)}>
        <label>
          <input type="checkbox" 
          		 checked={done} 
          		 onChange={this.handleCheck(id)} />
          <span>{name}</span>
        </label>
        <button onClick={this.handleDelete(id, name)} 
        		className="btn btn-danger" 
        		style={{ display: this.state.mouse ? 'block' : 'none' }}>删除</button>
      </li>
    );
  }
}

export default Item;

🛠Item-index.css

/*item*/
li {
  list-style: none;
  height: 36px;
  line-height: 36px;
  padding: 0 5px;
  border-bottom: 1px solid #ddd;
}

li label {
  float: left;
  cursor: pointer;
}

li label li input {
  vertical-align: middle;
  margin-right: 6px;
  position: relative;
  top: -1px;
}

li button {
  float: right;
  display: none;
  margin-top: 3px;
}

li:before {
  content: initial;
}

li:last-child {
  border-bottom: none;
}

---

Footer部分

🛠Footer-index.jsx

import React, { Component } from 'react';
import './index.css'

class Footer extends Component {

  // 全选checkbox的回调
  handleCheckAll = (event) => {
    console.log(event.target.checked)
    this.props.checkAllTodo(event.target.checked)
  }

  // 清除所有已完成任务的回调
  handleClearAllDone = () => {
    this.props.clearAllDone()
  }


  render() {
    const { todos } = this.props
    // 已完成的个数
    const doneCount = todos.reduce((prev, currentTodo) => {
      return prev + (currentTodo.done ? 1 : 0)
    }, 0)
    // 总数
    const total = todos.length

    return (
      <div className="todo-footer">
        <label>
          <input type="checkbox" 
          		checked={doneCount === total && total !== 0 ? true : false} 
          		onChange={this.handleCheckAll} />
        </label>
        <span>
          <span>已完成{doneCount}</span> / 全部{total}
        </span>
        <button onClick={this.handleClearAllDone} 
        		className="btn btn-danger">清除已完成任务</button>
      </div>
    );
  }
}

export default Footer;

🛠Footer-index.css

/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative