redux源码阅读（进行中）

入口：index.js（目录）重点标红

import createStore from './createStore'
import combineReducers from './combineReducers'
import bindActionCreators from './bindActionCreators'
import applyMiddleware from './applyMiddleware'
import compose from './compose'
import warning from './utils/warning'
import __DO_NOT_USE__ActionTypes from './utils/actionTypes'
// types// store
export {CombinedState, PreloadedState, Dispatch, Unsubscribe,  Observable, Observer, Store, StoreCreator, StoreEnhancer, StoreEnhancerStoreCreator,ExtendState} from './types/store'
// reducers
export {Reducer,ReducerFromReducersMapObject,ReducersMapObject,StateFromReducersMapObject,ActionFromReducer,ActionFromReducersMapObject} from './types/reducers'
// action creators
export { ActionCreator, ActionCreatorsMapObject } from './types/actions'
// middleware
export { MiddlewareAPI, Middleware } from './types/middleware'
// actions
export { Action, AnyAction } from './types/actions'

export {
  createStore,combineReducers,bindActionCreators,applyMiddleware,compose,__DO_NOT_USE__ActionTypes
}

初始化：createStore.js

createStore接受三个参数（reducer、preloadedState？、enhancer）

首先看用法:

 const store = createStore( rootReducer, applyMiddleware(thunk) ); 此处的 applyMiddleware(trunk) 即 enhancer,支持如下

 if (typeof preloadedState === 'function' && typeof enhancer === 'undefined') { enhancer = preloadedState as StoreEnhancer<Ext, StateExt> preloadedState = undefined } getState方法：

let currentState = preloadedState as S //preloadState参数

let isDispatching = false //加锁，不可以同时改变数据和获取数据

 function getState(): S {
    if (isDispatching) {
      throw new Error(
        'You may not call store.getState() while the reducer is executing. ' +
          'The reducer has already received the state as an argument. ' +
          'Pass it down from the top reducer instead of reading it from the store.'
      )
    }

    return currentState as S
  }

sunscribe方法：

let currentReducer = reducer

let currentListeners: (() => void)[] | null = []

let nextListeners = currentListeners

  function subscribe(listener: () => void) {
    if (typeof listener !== 'function') {
      throw new Error('Expected the listener to be a function.')
    }
　　//锁
    if (isDispatching) {
      throw new Error(
        'You may not call store.subscribe() while the reducer is executing. ' +
          'If you would like to be notified after the store has been updated, subscribe from a ' +
          'component and invoke store.getState() in the callback to access the latest state. ' +
          'See https://redux.js.org/api-reference/store#subscribelistener for more details.'
      )
    }

    let isSubscribed = true

    ensureCanMutateNextListeners()
    nextListeners.push(listener)

　　function ensureCanMutateNextListeners() {

　　 if (nextListeners === currentListeners) {

　　 nextListeners = currentListeners.slice()

　　 }

return function unsubscribe() {
      if (!isSubscribed) {
        return
      }
　　　　//锁
      if (isDispatching) {
        throw new Error(
          'You may not unsubscribe from a store listener while the reducer is executing. ' +
            'See https://redux.js.org/api-reference/store#subscribelistener for more details.'
        )
      }

      isSubscribed = false

      ensureCanMutateNextListeners()
      const index = nextListeners.indexOf(listener)
      nextListeners.splice(index, 1)
      currentListeners = null
    }
  }

来源：https://www.cnblogs.com/xinfangzhang/p/12446592.html

标签

redux

源码

types