import{ createStore }from'redux';importcreateReducerfrom'./reducers';exportdefaultfunctionconfigureStore(initialState) {conststore =createStore(createReducer(), initialState); store.asyncReducers= {};returnstore; }exportfunctioninjectAsyncReducer(store, name, asyncReducer) { store.asyncReducers[name] = a...
Therefore, the reducer function always returns a new state object.Updating state after immutable data structure since we have spread operator makes sure that it will only update the desired property without modifying other state properties.In Redux, there is a core concept of Store. A store is ...
Redux第一次会使用undefined状态来调用reducer。此时可以返回应用的初始state: import { VisibilityFilters } from './actions' const initialState = { visibilityFilter: VisibilityFilters.SHOW_ALL, todos: [] } function todoApp(state, action) { if (typeof state === 'undefined') { return initialState ...
function counter(state = 0, action) { switch (action.type) { case 'INCREMENT': return state + 1; case 'DECREMENT': return state - 1; default: return state; } } 这是典型 Redux reducer 的基本结构。# State 的基本结构Redux 鼓励你根据要管理的数据来思考你的应用程序。数据就是你应用的 ...
在一个reducer函数中,如果没有转到switch块,我们通常会返回默认状态。functionreducer(state = initialState, action: any): any { case SOME_TYPE: someBoolean:false} }我尝试了dispatch 浏览7提问于2019-11-20得票数 0 4回答 为什么reduxreducer变得“未定义”,而不是初始状态?
exportdefaultfunctioncounter(state =0, action) {switch(action.type) {case'INCREMENT':returnstate +1case'DECREMENT':returnstate -1default:returnstate } } reducers/index.js import{ combineReducers }from'redux'importtodosfrom'./todos'importcounterfrom'./counter'export default combineReducers({ ...
我们将以指定 state 的初始状态作为开始。Redux 首次执行时,state 为undefined,此时我们可借机设置并返回应用的初始 state。 import{VisibilityFilters}from'./actions'constinitialState={visibilityFilter:VisibilityFilters.SHOW_ALL,todos:[]}functiontodoApp(state,action){if(typeofstate==='undefined'){returninitial...
在Redux中，通常不建议reducer直接分派动作。Reducer应该是纯函数，将当前状态和动作作为输入，并根据动作的...
Redux 首次执行时,state 为 undefined,此时我们可借机设置并返回应用的初始 state。import { VisibilityFilters } from './actions' const initialState = { visibilityFilter: VisibilityFilters.SHOW_ALL, todos: [] }; function todoApp(state, action) { if (typeof state === 'undefined') { return ...
/** * createStore * @param {reducer} reducer为function,当dispatch一个action时,此函数接收action来更新state * @param {preloadState} 初始化State * @param {enhancer} enhancer 为function。用来增强store * @return {Object} 返回一个包含dispatch和subscribe等函数的对象 */ export default function createStore...