![](/img/trans.png)
[英]How do I console.log state.car.price in my reducer function
[英]Unable to update the state of my app, console.log inside reducer shows that object has changed, but the state remains same
玩 redux 让我很困惑。 一些如何更新对象中仅一个键的状态变得如此困难的原因。
当用户选中组件内的复选框时,将分派一个操作。 当它被检查时,产品的状态应该从 NEW 变为 RESERVED:
// ProductRow.js
const ProductRow = React.createClass({
propTypes: {
item: PropTypes.object.isRequired,
onChange: PropTypes.func.isRequired
},
render () {
const { code, name, imageUrl, description } = this.props.item.product
const {status} = this.props.item
const {onChange} = this.props
return (
<div>
<label htmlFor={code}>
<input type='checkbox' id={code} onClick={onChange} value={status} />
<img src={imageUrl} />
<div className='name'>{name}</div>
<div className='description'>{description}</div>
</label>
</div>
)
}
})
ProductRow 的父组件是 ProductList:
const ProductList = React.createClass({
propTypes: {
items: PropTypes.array.isRequired,
dispatchSetStatusToReservedForItem: PropTypes.func
},
handleProductCheckBoxClick (item) {
if (document.getElementById(item.product.code).checked) {
this.props.dispatchSetStatusToReservedForItem(item)
}
},
render () {
const {items} = this.props
return (
<div>
{
items.map((item) => {
return (
<ProductRow key={item.id} onChange={this.handleProductCheckBoxClick.bind(this, item)} item={item} />
)
})
}
</div>
)
}
})
当复选框被勾选时,我会收到 reducer 内部的 console.log 警报,它显示了正确的输出,即数组“item”中的正确对象已更改,但不知何故它没有反映在 UI 和 rect 开发人员工具中.
//Reducer const DEFAULT_STATE = { shoppingCartData: shoppingCartData }
const setStatusToReserved = (state, action) => {
const {items} = state.shoppingCartData.data
items.map(item => {
if(action.item.id === item.id) {
console.log(Object.assign({},action.item, {status: 'RESERVED'}))
return Object.assign({}, action.item, {status: 'RESERVED'})
}
})
}
const rootReducer = (state = DEFAULT_STATE, action) => {
switch (action.type) {
case ACTIONS.SET_STATUS_TO_RESERVED:
return setStatusToReserved(state, action)
default:
return DEFAULT_STATE
}
}
export default rootReducer
如果更改状态的一部分,则需要为状态创建新的对象引用。 按照您的方式,您的旧状态仍将===
新状态,因此 redux 无法知道它已更改。
此外,您的setStatusToReserved
函数根本不返回任何内容!
你的状态不应该像现在这样嵌套很深,我认为还有更多的工作要做,但向前迈出的一步是:
const setStatusToReserved = (state, action) => {
const {items} = state.shoppingCartData.data
const newItems = items.map(item => {
if(action.item.id === item.id) {
console.log(Object.assign({},action.item, {status: 'RESERVED'}))
return Object.assign({}, action.item, {status: 'RESERVED'})
}
})
return {
...state,
shoppingCartData: {
...shoppingCartData.data,
items: newItems
}
}
}
我强烈建议观看免费并解决所有这些问题的Egghead Redux 系列。
我大大简化了减速器,我只从商店获取状态(通过设置初始状态),我想更改并将产品列表设为我的智能组件(因为这是我唯一想要更改状态的组件) . 我认为我对 reducer 所做的更改和仔细挑选了我的智能组件有所帮助。 感谢视频推荐,Dan 的视频帮助很大。
import { ACTIONS } from './actions'
/**
* Returns an updated array with check product status set to RESERVED
* @param state
* @param action
* @return {[*,*,*]}
*/
const setStatusToReserved = (state, action) => {
let updateStatus = Object.assign({}, action.item, {status: 'RESERVED'})
let index = state.indexOf(action.item)
return [...state.slice(0, index), updateStatus, ...state.slice(index + 1)]
}
/**
* Returns an updated array with check product status set to NEW
* @param state
* @param action
* @return {[*,*,*]}
*/
const setStatusToNew = (state, action) => {
let updateStatus = Object.assign({}, action.item, {status: 'NEW'})
let index = state.indexOf(action.item)
return [...state.slice(0, index), updateStatus, ...state.slice(index + 1)]
}
/**
* Function that takes the current state and action and return new state
* Initial state is set to product items
* @param state
* @param action
* @return {{}}
*/
const rootReducer = (state = {}, action) => {
switch (action.type) {
case ACTIONS.SET_STATUS_TO_RESERVED:
return setStatusToReserved(state, action)
case ACTIONS.SET_STATUS_TO_NEW:
return setStatusToNew(state, action)
default:
return state
}
}
export default rootReducer
[PROD_FORM_DETAILS_SUCCESS]: (state, { payload: { ProdDetailsData } }) =>
{
console.log(" reducer ===================== " , catalogueProductDetailsData);
return {
...state,
catalogueProductDetailsData,
isFetching: false,
}},
[CREATE_USER_FORM]: (state, {}) => {
console.log(" reducer =======CREATE_USER_FORM ============== ");
return {
...state,
isFetching: false,
};
},
//Without console
[CREATE_USER_FORM]: (state, {}) => ({
...state,
isFetching: true,
}),
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.