此文项目代码：https://github.com/bei-yang/I-want-to-be-an-architect
码字不易，辛苦点个star，感谢！

引言

---

此篇文章主要涉及以下内容：

1. redux
2. redux中间件
3. react-router4

学习资源

---

• redux
• react-redux
• react-router

起步

---

redux上手

---

安装

npm i redux --save

redux中首先我们要了解的就是store，这就是帮咱们管理数据的政委，具有全局唯一性，所有的数据都在这一个数据源里进行管理，但是本身redux和react并没有直接的联系，可以单独试用，复杂的项目才需要redux来管理数据，简单项目state+props+context足矣。
redux之所以难上手，是因为上来就有太多的概念需要学习，用一个累加器举例：

1. 需要一个store来存储数据
2. store里的state是放置数据的地方
3. 通过dispatch一个action来提交对数据的修改
4. 请求提交到reducer函数里，根据传入的action和state，返回新的state

有点绕，贴代码

使用

store.js

import { createStore } from 'redux'

const counterReducer = (state = 0, action) => {
  switch (action.type) {
    case 'add':
      return state + 1
    case 'minus':
      return state - 1
    default:
      return state
  }
}

const store = createStore(counterReducer)

export default store

应用

app.js

import React from 'react'
import store from './store'
class App extends React.Component{
  render(){
    return <div>
      <p>{store.getState()}</p>
      <div>
        <button onClick={()=>store.dispatch({type:"add"})}>+</button>
        <button onClick={()=>store.dispatch({type:"minus"})}>-</button>
      </div>
    </div>
 }
}
export default App

订阅

index.js

import React from 'react'
import ReactDom from 'react-dom'
import App from './App'
import store from './store'
const render = ()=>{
 ReactDom.render(
  <App/>,
  document.querySelector('#root')
)
}
render()
store.subscribe(render)

react-redux

---

react整合redux，简化使用难度，需要react-redux的支持
提供了两个api

1. provider顶级组件，提供数据
2. connect高阶组件，提供数据和方法

安装

npm i react-redux --save

注入store

index.js

import React from 'react'
import ReactDom from 'react-dom'
import App from './App'
import store from './store'

import { Provider } from 'react-redux'

ReactDom.render(
  // 内部是使用的上下文进行的传值
  <Provider store={store}>
    <App />
  </Provider>,
  document.querySelector('#root')
)

使用状态

app.js

import React from 'react'
import { connect } from 'react-redux'
const mapStateToProps = state => {
  return {
    num: state
  }
}
const mapDispatchToProps = dispatch => {
  return {
    add: () => dispatch({ type: 'add' }),
    minus: () => dispatch({ type: 'minus' })
  }
}
class App extends React.Component {
  render() {
    return (
      <div>
        <p>{this.props.num}</p>
        <div>
          <button onClick={() => this.props.add()}>+</button>
          <button onClick={() => this.props.minus()}>-</button>
        </div>
      </div>
    )
  }
}

export default connect(
  mapStateToProps,
  mapDispatchToProps
)(App)

装饰器写法

import React from 'react'
import { connect } from 'react-redux'

@connect(
  state => ({ num: state }),
  dispatch => ({
    add: () => dispatch({ type: 'add' }),
    minus: () => dispatch({ type: 'minus' })
  })
)
class App extends React.Component {
  render() {
    return (
      <div>
        <p>{this.props.num}</p>
        <div>
          <button onClick={() => this.props.add()}>+</button>
          <button onClick={() => this.props.minus()}>-</button>
        </div>
      </div>
    )
  }
}

export default App

异步

redux默认只支持同步，实现异步任务比如延迟，网络请求，需要中间件的支持，比如我们试用最简单的redux-thunk和redux-logger

npm i redux-thunk --save

1. Reducer：纯函数，只承担计算State的功能，不适合承担其他功能，也承担不了，因为理论上，纯函数不能进行读写操作。
2. View：与state一一对应，可以看作state的视觉层，也不合适承担其他功能。
3. Action：存放数据的对象，即消息的载体，只能被别人操作，自己不能进行任何操作。
4. 实际的reducer和action store都需要独立拆分文件。

试用redux-logger

store.js

import {applyMiddleware,createStore} from 'redux'
import logger from 'redux-logger'

const counterReducer = (state=0,action)=>{...}
const store=createStore(counterReducer,applyMiddleware(logger));

export default store

试用redux-thunk

import {applyMiddleware,createStore} from 'redux'
import logger from 'redux-logger'
import thunk from 'redux-thunk'

const counterReducer = (state=0,action)=>{...}
const store=createStore(counterReducer,applyMiddleware(logger,thunk));

export default store

应用

App.js

import React from 'react'
import { connect } from 'react-redux'
@connect(
  state => ({ num: state }),
  {
    add: () => ({ type: 'add' }),
    minus: () => ({ type: 'minus' }),
    asyncAdd: () => dispatch => {
      setTimeout(() => {
        // 实际的异步不在这里写
        // 异步结束后，手动执行dispatch
        dispatch({ type: 'add' })
      }, 1000)
    }
  }
)
class App extends React.Component {
  render() {
    return (
      <div>
           <p>{this.props.num}</p>
        <div>
              <button onClick={() => this.props.add()}>+</button>
              <button onClick={() => this.props.minus()}>-</button>
              <button onClick={() => this.props.asyncAdd()}>延迟添加</button>
        </div>
      </div>
    )
  }
}
export default App

代码需重构：抽离reducer和action，详情看代码中的store文件夹

react-router-4

---

安装

npm i --save react-router-dom

应用路由

index.js

import React from 'react'
import ReactDom from 'react-dom'
import { Provider } from 'react-redux'

import { applyMiddleware, createStore } from 'redux'
import logger from 'redux-logger'
import thunk from 'redux-thunk'
import { counterReducer } from './counter.redux'
import App from './App'

import { BrowserRouter } from 'react-router-dom'

const store = createStore(counterReducer, applyMiddleware(logger, thunk))

ReactDom.render(
  <BrowserRouter>
    <Provider store={store}>
      <App />
    </Provider>
  </BrowserRouter>,
  document.querySelector('#root')
)

配置、导航

app.js

import React from 'react'
import { connect } from 'react-redux'
import { add, minus, asyncAdd } from './counter.redux'
import { Route, Link } from 'react-router-dom'
function About() {
  return <div>About</div>
}
function Detail() {
  return <div>Detail</div>
}
@connect(
  state => ({ num: state }),
  { add, minus, asyncAdd }
)
class Counter extends React.Component {
  render() {
    return (
      <div>
           <p>{this.props.num}</p>
        <div>
              <button onClick={() => this.props.add()}>+</button>
              <button onClick={() => this.props.minus()}>-</button>
              <button onClick={() => this.props.asyncAdd()}>延迟添加</button>
        </div>
      </div>
    )
  }
}
class App extends React.Component {
  render() {
    return (
      <div>
        <ul>
          <Link to="/">累加器</Link> 
          <Link to="/about">About</Link> 
          <Link to="/detail">Detail</Link>
        </ul>
        <div>
          <Route exact path="/" component={Counter} />
          <Route path="/about" component={About} />
          <Route path="/detail" component={Detail} />
        </div>
      </div>
    )
  }
}
export default App

动态路由

使用:id的形式定义参数

<Route path="/detail/:id" component={Detail} />
function Detail(props){
 return <div>Detail :{props.match.params.id}</div>
}

路由守卫

// 路由守卫
// 希望用法：<PrivateRoute component={About} path="/about" ...>
const PrivateRoute = connect(state => ({ isLogin: state.user.isLogin }))(
  ({ component: Comp, isLogin, ...rest }) => {
    // 做认证
    // render:根据条件动态渲染组件
    return (
      <Route
        {...rest}
        render={props =>
          isLogin ? (
            <Comp />
          ) : (
            <Redirect
              to={{
                pathname: "/login",
                state: { redirect: props.location.pathname }
              }}
            />
          )
        }
      />
    );
  }
);

重点看RouteSample.js文件

你的赞是我前进的动力

求赞，求评论，求分享...