react-redux-Provider/connect

Provider

• 只有一个子组件，没有或者超过一个均会报错
• 有store属性，可以得到redux里所有的state
• Provider里所有的子组件都可以通过this.props得到state

import React from 'react'
import ReactDom from 'react-dom';
import { render } from 'react-dom'
import { Provider } from 'react-redux'
import { createStore } from 'redux'
import reducers from './reducers'
import App from './containers/App'
let store = createStore(reducers)
ReactDom.render(
      
        
      ,
      document.getElementById('root'));

connect

• connect里有subscribe()，可以自动监听变化
• mapStateToProps 将store中state数据映射成props对象，展示组件就可以通过this.props.来访问容器组件返回的数据
• mapDispatchToProps将action作为props绑定到组件上

import {connect} from 'react-redux';
import App from '../components/App';
const mapStateToProps = (state)=> {
    return{
       count: state.count
      }
};
const mapDispatchToProps = (dispatch)=> {
    return {
        onAdd: (content)=> {
            dispatch({type:'ADD',content});
        }
    }
};
export default connect(mapStateToProps, mapDispatchToProps)(App);