【react】---手動封裝一個簡易版的redux---【巷子】

export let createStore = (reducer)=>{
    //定義默認的state
    let state = {};

    //定義默認的action
    let actionTypes = "@@redux/INIT"+Math.random();
    let initAction = {type:actionTypes}

    //將所以需要監聽的函數放在這個里面
    let listeners = []

    //定義getState函數
    let getState = ()=>state;

    //定義事件訂閱函數
    let subscribe = (cb)=>{
        listeners.push(cb);
    }

    //定義事件派發函數 用來調用action
    let dispatch = (action=initAction)=>{
       
        //調用reducer獲取新的state
        state = reducer(state,action);

        //遍歷所以需要監聽的函數
        listeners.map((cb)=>{
            cb();
        })
        

    }
    dispatch();

    return {
        getState,
        dispatch,
        subscribe
    }
}

const combineReducers = (reducers)=>{

 

　　let newState = {};

　　return function(state,action){

 

　　　　for(var key in reducers){

　　　　　　newState[key] = reducers[key](state[key],action)

　　　　}

 

　　　　return newState;

　　}

}