React生态篇-使用redux

1，什么是redux

Redux是一个用来管理管理数据状态和UI状态的JavaScript应用工具。随着JavaScript单页应用（SPA）开发日趋复杂，JavaScript需要管理比任何时候都要多的state（状态），Redux就是降低管理难度的。（Redux支持React，Angular、jQuery甚至纯JavaScript）
react-redux工作流程

安装redux

npm install --save redux

简单使用
在src下新建store文件夹，创建仓库管理文件index.js

import { createStore, applyMiddleware, compose } from 'redux'  // 引入createStore方法
import reducer from "./reducer"
const store = createStore(reducer) // 创建数据存储仓库
export default store                 //暴露出去

同时创建reducer.js文件

//定义初始state
const defaultState = {
  inputValue: '请输入待办事项',
  list: [
    '早上4点起床，锻炼身体',
    '中午下班游泳一小时'
  ]
}
export default (state = defaultState, action) => {
  return state
}

组件中使用state的值

import React, { Component } from 'react';
//组件中引入store
import store from './store'
class TodoList extends Component {
  constructor(props) {
    super(props)
    #获取store中state的值
    this.state = store.getState();
    this.clickBtn = this.clickBtn.bind(this)

  }
  render() {
    return (
           <div>
                <Input placeholder={this.state.inputValue} style={{ width: '250px', marginRight: '10px' }}  value={this.state.inputValue} />
                <Button type="primary" onClick={clickBtn}>增加</Button>
            </div>
            <div style={{ margin: '10px', width: '300px' }}>
                <List bordered
                    dataSource={this.state.list}
                    renderItem={(item, index) => (<List.Item onClick={() => {
                       deleteItem(index)
                    }}>{item}</List.Item>)}></List>
            </div>
    );
  }
    deleteItem(index) {
         console.log(index)
  }
}

export default TodoList;

二，安装redux谷歌调试工具

翻墙下载redux_dev_tool,
在store/index文件下添加

import { createStore, applyMiddleware, compose } from 'redux'  // 引入createStore方法
import reducer from "./reducer"
//const composeEnhancers = 
//const enhancers = composeEnhancers(applyMiddleware(thunk)) 
const store = createStore(
                           reducer,
                           window.__REDUX_DEVTOOLS_EXTENSION_ && window.__REDUX_DEVTOOLS_EXTENSION_()
                         ) // 创建数据存储仓库,存在调试工具，开启工具
export default store    

三，操作store 改变

import React, { Component } from 'react';
//组件中引入store
import store from './store'
class TodoList extends Component {
  constructor(props) {
    super(props)
    #获取store中state的值
    this.state = store.getState();
    this.clickBtn = this.clickBtn.bind(this)
        this.changeInputValue = this.changeInputValue.bind(this)
    #添加订阅     #新版本不用添加订阅 但是input value变化需要使用订阅
    store.subscribe(this.storeChange)
    this.storeChange = this.storeChange.bind(this)
  }
  render() {
    return (
           <div>
                <Input placeholder={this.state.inputValue} style={{ width: '250px', marginRight: '10px' }} onChange={()=>{this.changeInputValue}  value={this.state.inputValue} />
                <Button type="primary" onClick={this.clickBtn}>增加</Button>
            </div>
            <div style={{ margin: '10px', width: '300px' }}>
                <List bordered
                    dataSource={this.state.list}
                    renderItem={(item, index) => (
                      <List.Item onClick={() => {deleteItem(index)}}>{item}</List.Item>
                                        )}></List>
            </div>
    );
  }
    changeInputValue(e){
      //声明action对象
    const action ={
        type:'changeInput',
      value:e.target.value
    }
    //调用dispatch
    store.dispatch(action)
  }
  // 订阅更新
  storeChange() {
    this.setState(store.getState())
  }
    // 添加按钮事件
    clickBtn(){
        const action ={
        type:'addItem',
    }
        store.dispatch(action)
    }
    //点击删除事件
    deleteItem(index) {
    const action = {
        type:'deleteItem',
      index
    }
    store.dispatch(action)
  }
}

export default TodoList;

在reducer.js中执行对应type类型的操作

//定义初始state
const defaultState = {
  inputValue: '请输入待办事项',
  list: [
    '早上4点起床，锻炼身体',
    '中午下班游泳一小时'
  ]
}
export default (state = defaultState, action) => {
  #reducer里只能接受state 不能改变state
  if(action.type == 'changeInput'){
    let newState = JSON.pares(JSON.stringify(state)) //深拷贝state
    newState.inputValue = action.value
    return newState
  }
  //添加事件
  if(action.type == 'addItem'){
    let newState = JSON.pares(JSON.stringify(state)) //深拷贝state
    newState.list.push(newState.inputValue)
    newState.inputValue = '' //增加完成，设置为空
    return newState
  }
  //删除事件
  if(action.type == 'deleteItem'){
    let newState = JSON.pares(JSON.stringify(state)) //深拷贝state
    newState.list.splice(action.index,1)
    return newState
  }
  return state
}

三，写redux的小技巧

1. 独立type文件
   在store中新建文件actionType.js

//定义常量
export const CHANGE_INPUT = 'changeInput'
export const ADD_ITEM = 'addItem'
export const DELETE_ITEM = 'deleteItem'
export const GET_LIST = 'getList'

在组件中引入actionType文件

import React, { Component } from 'react';
//组件中引入store
import store from './store'
import { CHANGE_INPUT, ADD_ITEM, DELETE_ITEM, GET_LIST } from './store/actionType'
class TodoList extends Component {
  constructor(props) {
    super(props)
    #获取store中state的值
    this.state = store.getState();
    this.clickBtn = this.clickBtn.bind(this)
        this.changeInputValue = this.changeInputValue.bind(this)
    #添加订阅     #新版本不用添加订阅 但是input value变化需要使用订阅
    store.subscribe(this.storeChange)
    this.storeChange = this.storeChange.bind(this)
  }
  render() {
    return (
           <div>
                <Input placeholder={this.state.inputValue} style={{ width: '250px', marginRight: '10px' }} onChange={()=>{this.changeInputValue}  value={this.state.inputValue} />
                <Button type="primary" onClick={this.clickBtn}>增加</Button>
            </div>
            <div style={{ margin: '10px', width: '300px' }}>
                <List bordered
                    dataSource={this.state.list}
                    renderItem={(item, index) => (
                      <List.Item onClick={() => {deleteItem(index)}}>{item}</List.Item>
                                        )}></List>
            </div>
    );
  }
    changeInputValue(e){
      //声明action对象
    #使用引入的常量替换
    const action ={
        type:CHANGE_INPUT,
      value:e.target.value
    }
    //调用dispatch
    store.dispatch(action)
  }
  // 订阅更新
  storeChange() {
    this.setState(store.getState())
  }
    // 添加按钮事件
    clickBtn(){
        const action ={
        type:ADD_ITEM,
    }
        store.dispatch(action)
    }
    //点击删除事件
    deleteItem(index) {
    const action = {
        type:DELETE_ITEM,
      index
    }
    store.dispatch(action)
  }
}

export default TodoList;

在reducer.js中也进行引入

import { CHANGE_INPUT, ADD_ITEM, DELETE_ITEM } from './actionType'
//定义初始state
const defaultState = {
  inputValue: '请输入待办事项',
  list: [
    '早上4点起床，锻炼身体',
    '中午下班游泳一小时'
  ]
}
export default (state = defaultState, action) => {
  #reducer里只能接受state 不能改变state
  if(action.type == CHANGE_INPUT){
    let newState = JSON.pares(JSON.stringify(state)) //深拷贝state
    newState.inputValue = action.value
    return newState
  }
  //添加事件
  if(action.type == ADD_ITEM){
    let newState = JSON.pares(JSON.stringify(state)) //深拷贝state
    newState.list.push(newState.inputValue)
    newState.inputValue = '' //增加完成，设置为空
    return newState
  }
  //删除事件
  if(action.type == DELETE_ITEM){
    let newState = JSON.pares(JSON.stringify(state)) //深拷贝state
    newState.list.splice(action.index,1)
    return newState
  }
  return state
}

2. 集中整理action派发
   在store中新建actionCreator.js文件

import { CHANGE_INPUT, ADD_ITEM, DELETE_ITEM } from './actionType'

export const changeInputAction = (value) =>({
    type:CHANGE_INPUT,
  value
})

export const addItemAction = () =>({
    type:ADD_ITEM,
})

export const deleteItemAction = (index) =>({
    type:DELETE_ITEM,
  index
})

在组件中引入actionCreator.js

import React, { Component } from 'react';
//组件中引入store
import store from './store'
//引入actionCreator.js
import { changeInputAction,addItemAction,deleteItemAction } from './store/actionCreator'
class TodoList extends Component {
  constructor(props) {
    super(props)
    #获取store中state的值
    this.state = store.getState();
    this.clickBtn = this.clickBtn.bind(this)
        this.changeInputValue = this.changeInputValue.bind(this)
    #添加订阅     #新版本不用添加订阅 但是input value变化需要使用订阅
    store.subscribe(this.storeChange)
    this.storeChange = this.storeChange.bind(this)
  }
  render() {
    return (
           <div>
                <Input placeholder={this.state.inputValue} style={{ width: '250px', marginRight: '10px' }} onChange={()=>{this.changeInputValue}  value={this.state.inputValue} />
                <Button type="primary" onClick={this.clickBtn}>增加</Button>
            </div>
            <div style={{ margin: '10px', width: '300px' }}>
                <List bordered
                    dataSource={this.state.list}
                    renderItem={(item, index) => (
                      <List.Item onClick={() => {deleteItem(index)}}>{item}</List.Item>
                                        )}></List>
            </div>
    );
  }
    changeInputValue(e){
    const action = changeInputAction(e.target.value)
    //调用dispatch
    store.dispatch(action)
  }
  // 订阅更新
  storeChange() {
    this.setState(store.getState())
  }
    // 添加按钮事件
    clickBtn(){
        const action =addItemAction()
        store.dispatch(action)
    }
    //点击删除事件
    deleteItem(index) {
    const action = deleteItemAction(index)
    store.dispatch(action)
  }
}

export default TodoList;