redux中间件之monkeying patch

我们想在reudx代码间插入想要做的逻辑，其实就是中间件。

1.基本做法(假设已经配置好react-redux也就是store/index,addAction和subAction是action逻辑)

import store from './store/index.js'
import {addAction,subAction} from './store/actionCreators'
//1.基本做法
console.log("dispatch前---dispathing", addAction(10))
store.dispatch(addAction(10))
console.log("dispatch后---new state", store.getState())
console.log("dispatch前---dispathing", addAction(15))
store.dispatch(addAction(15))
console.log("dispatch后---new state", store.getState())

这样做简单但是调用起来很复杂

2.封装函数

function dispatchAndLogging(action){
  console.log("dispatch前---dispathing", action)
  store.dispatch(action)
  console.log("dispatch后---new state", store.getState())
}
dispatchAndLogging(addAction(10))
dispatchAndLogging(addAction(15))

3.在函数的基础上修改原有的dispatch

const next = store.dispatch
function dispatchAndLogging2(action){
  console.log("dispatch前---dispathing", action)
  next(action)
  console.log("dispatch后---new state", store.getState())
}
store.dispatch = dispatchAndLogging2
store.dispatch(addAction(10))
store.dispatch(addAction(5))

这就不会影响原来的调用，也就是monkeyingpatch。但是可能污染了原来的store

4.最后封装一下再使用

function patchLogging(store) {
  const next = store.dispatch
  function dispatchAndLogging(action){
    console.log("dispatch前---dispathing", action)
    next(action)
    console.log("dispatch后---new state", store.getState())
  }
  return dispatchAndLogging
}
patchLogging(store)
//应用封装好的中间件
function applyMiddlewares(...middlewares){
  middlewares.forEach(middleware=>{
    store.dispatch=middleware(store)
  })
}
applyMiddlewares(patchLogging)