React 应用

古城微笑少年丶 2022-10-14 01:17 91阅读 0赞

## React 应用 ##

[尚硅谷 2021 版 React 技术全家桶全套完整版（零基础入门到精通/男神天禹老师亲授）][2021 _ React]

### React 脚手架 ###

1.  xxx脚手架：用来帮助程序员快速创建一个基于 xxx 库的模板项目
2.  React 提供了一个用于创建 React 项目的脚手架库：`create-react-app`
3.  项目整体技术架构为：react + webpack + es6 + eslint
4.  使用脚手架开发的项目特点：模板化、组件化、工程化

**安装**

1.  全局安装：`npm i -g create-react-app`
2.  切换到想创建项目的目录，`create-react-app hello-react`
3.  进入项目文件夹：`cd hello-react`
4.  启动项目：`npm start`

*  `%PUBLIC_URL%` 代表 public 文件夹的路径
 *  `reportWebVitals` 记录页面性能，其使用 `web-vitals` 库
 *  `setupTests` 组件单元测试，其使用 `@testing-library/jest-dom`

安装插件 `ES7 React/Redux/GraphQL/React-Native snippets`

**样式模块化**

1.  使用预编译语言比如：Less、Scss
2.  把 css 名改为 `index.module.css`
    
    `import xx from './index.module.css'` `<h2 className={xx.xx}>`

**组件化编码流程**

1.  拆分组件：拆分页面，抽取组件
2.  实现静态组件，使用组件实现静态页面效果
3.  实现动态组件
    
    动态显示初始化数据（数据类型、数据名称、保存在哪个组件）
    
    交互（从绑定事件监听开始）

### TODO List ###

*  生成唯一 UUID

yarn add nanoid

*  点击复选框切换提示是否选中及附带信息
 *  点击按钮

handleCheck = id => {
      return e => {
        this.props.updateTodo(id, e.target.checked)
      }
    }
    <input type="checkbox" defaultChecked={false} onChange={this.handleCheck(id)} />
    
    
    handleDelete = id => {
      if (window.confirm('确定删除吗？')) {
        this.props.deleteTodo(id)
      }
    }
    <button onClick={() => this.handleDelete(id)}>删除</button>

1.  拆分组件、实现静态组件，注意：className、style 的写法
2.  动态初始化列表，如何确定将数据放在哪个组件的 state 中
    
     *  某个组件使用：放在自身的 state 中
     *  某个组件使用：放在他们共同的父组件 state 中（官方称此操作：状态提升）
3.  父子之间通信
    
     *  【父组件】给【子组件】传递数据：通过 props 传递
     *  【子组件】给【父组件】传递数据：通过 props 传递，要求父提前给子传递一个函数
4.  注意 defaultChecked 和 checked 区别，类似的还有：defaultValue 和 value
5.  状态在哪里，操作状态的方法就在哪里

#### App.jsx ####

import React, { Component } from 'react'
    import './index.css'
    import Header from './component/Header'
    import List from './component/List'
    import Footer from './component/Footer'
    
    export default class App extends Component {
      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 = todoObj => {
        const { todos } = this.state
        const newTodos = [todoObj, ...todos]
        this.setState({ todos: newTodos })
      }
      updateTodo = (id, done) => {
        const { todos } = this.state
        const newTodos = todos.map(todoObj => {
          if (todoObj.id === id) return { ...todoObj, done }
          else return todoObj
        })
        this.setState({ todos: newTodos })
      }
      deleteTodo = id => {
        const { todos } = this.state
        const newTodos = todos.filter(todoObj => todoObj.id !== id)
        this.setState({ todos: newTodos })
      }
      checkAllTodo = done => {
        const { todos } = this.state
        const newTodos = todos.map(todoObj => {
          return { ...todoObj, done }
        })
        this.setState({ todos: newTodos })
      }
      clearAllDone = () => {
        const { todos } = this.state
        const newTodos = todos.filter(todoObj => {
          return !todoObj.done
        })
        this.setState({ todos: newTodos })
      }
      render() {
        const { todos } = this.state
        return (
          <div className="todo-container">
            <div className="todo-wrap">
              <Header addTodo={this.addTodo} />
              <List todos={todos} updateTodo={this.updateTodo} deleteTodo={this.deleteTodo} />
              <Footer todos={todos} checkAllTodo={this.checkAllTodo} clearAllDone={this.clearAllDone} />
            </div>
          </div>
        )
      }
    }

#### Header.jsx ####

import React, { Component } from 'react'
    import PropTypes from 'prop-types'
    import { nanoid } from 'nanoid'
    import './index.css'
    
    export default class Header extends Component {
      static propTypes = {
        addTodo: PropTypes.func.isRequired,
      }
      handleKeyUp = e => {
        const { keyCode, target } = e
        if (keyCode !== 13) return
        if (target.value.trim() === '') return
        const todoObj = { id: nanoid(), name: target.value, done: false }
        this.props.addTodo(todoObj)
        target.value = ''
      }
      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>
        )
      }
    }

#### List.jsx ####

import React, { Component } from 'react'
    import Item from '../Item'
    import PropTypes from 'prop-types'
    import './index.css'
    
    export default class List extends Component {
      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>
        )
      }
    }

#### Item.jsx ####

import React, { Component } from 'react'
    import './index.css'
    
    export default class Item extends Component {
      state = { mouse: false }
      handleMouse = flag => {
        return () => {
          this.setState({ mouse: flag })
        }
      }
      handleCheck = id => {
        return e => {
          this.props.updateTodo(id, e.target.checked)
        }
      }
      handleDelete = id => {
        if (window.confirm('确定删除吗？')) {
          this.props.deleteTodo(id)
        }
      }
      render() {
        const { id, name, done } = this.props
        const { mouse } = this.state
        return (
          <li style={
       { backgroundColor: mouse ? '#ddd' : '#fff' }} onMouseLeave={this.handleMouse(false)} onMouseEnter={this.handleMouse(true)}>
            <label>
              <input type="checkbox" checked={done} onChange={this.handleCheck(id)} />
              <span>{name}</span>
            </label>
            <button onClick={() => this.handleDelete(id)} className="btn btn-danger" style={
       { display: mouse ? 'block' : 'none' }}>
              删除
            </button>
          </li>
        )
      }
    }

#### Footer.jsx ####

import React, { Component } from 'react'
    import './index.css'
    
    export default class Footer extends Component {
      handleCheckAll = e => {
        this.props.checkAllTodo(e.target.checked)
      }
      handleClearAllDone = () => {
        this.props.clearAllDone()
      }
      render() {
        const { todos } = this.props
        const doneCount = todos.reduce((pre, cur) => pre + (cur.done ? 1 : 0), 0)
        const total = todos.length
        return (
          <div className="todo-footer">
            <label>
              <input type="checkbox" onChange={this.handleCheckAll} checked={(doneCount === total) & (total !== 0) ? true : false} />
            </label>
            <span>
              <span>已完成{doneCount}</span> / 全部{total}
            </span>
            <button className="btn btn-danger" onClick={this.handleClearAllDone}>
              清除已完成任务
            </button>
          </div>
        )
      }
    }

[2021 _ React]: https://www.bilibili.com/video/BV1wy4y1D7JT?p=35&spm_id_from=pageDriver