Redux之源码分析（九）

# 一、index.js

https://github.com/reactjs/redux/blob/master/src/index.js

• 暴露了几个核心API

import createStore from './createStore';
import combineReducers from './utils/combineReducers';
import bindActionCreators from './utils/bindActionCreators';
import applyMiddleware from './utils/applyMiddleware';
import compose from './utils/compose';

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

# 二、createStore.js

https://github.com/reactjs/redux/blob/master/src/createStore.js

• redux.createStore(reducer, initialState) 传入了reducer、initialState，并返回一个store对象
• store对象对外暴露了dispatch、getState、subscribe方法
• store对象通过getState() 获取内部状态
• initialState为 store 的初始状态，如果不传则为undefined
• store对象通过reducer来修改内部状态
• store对象创建的时候，内部会主动调用dispatch({ type: ActionTypes.INIT });来对内部状态进行初始化。通过断点或者日志打印就可以看到，store对象创建的同时，reducer就会被调用进行初始化