react_3/redux

flux是个数据层框架,因为flux数据都存储在store中,所以推出了redux

yarn add redux

redux提供的创建store方法：

import { createStore } from ‘redux‘
import reducer from ‘./reducer‘
const store = createStore(reducer)
export default store

redux的核心API

1. createStore(生成store)

   const store = createStore(reducer, {
   inputValue: ‘‘,
   list: []
   })

2. store.dispatch(触发state改变的唯一途径)

   store.dispatch(action)    //把action发送到store中

3. store.getState(获取整个state树)

   this.state = store.getState()   //取得当前时刻的state

4. store.subscribe(监听)redux自动发布,只需监听

   store.subscribe(this.handleStoreChange.bind(this))

5. unsubscribe(取消监听)

   const unsubscribe = store.subscribe(this.handleStoreChange.bind(this))
   unsubscribe()

Redux三大原则

1. redux和store建议只有一个
2. 只有store自己可以改变自己
3. reducer是一个纯函数(给入固定的输入一定会有固定的输出,禁止使用ajax,时间戳)

reaux与flux的差异

Redux没有分发器Dispatcher,增加了Reducers