[英]Redux action uncaught in reducer because of mutated state
您可以假設以下變量:
click = true
categories = [
{title: "all", onClick: false},
{title: "video", onClick: false},
{title: "gif", onClick: false},
{title: "website", onClick: false}
]
finalCategories = [
{title: "all", onClick: true},
{title: "video", onClick: true},
{title: "gif", onClick: true},
{title: "website", onClick: true}
]
我在這里有一組redux動作:
import * as actionTypes from './actionTypes';
import {beginAjaxCall, ajaxCallError} from './ajaxStatusActions';
import * as Utils from './utils/dashboardActionsUtils';
export function updateCategoriesSuccess(categories) {
return {type: actionTypes.UPDATE_CATEGORIES_SUCCESS, categories};
}
export function categoryAllClick(categories, click) {
return function(dispatch) {
dispatch(beginAjaxCall());
const finalCategories = Utils.updateMenuOnAll(categories, click);
dispatch(updateCategoriesSuccess(finalCategories));
};
}
哪里:
export function updateMenuOnAll(menu, click) {
const finalMenu = Object.assign([], menu);
if (click) {
finalMenu.map(item => item.onClick = true);
} else {
finalMenu.map(item => item.onClick = false);
}
return finalMenu;
}
但是,當我調用categoryAllClick(categories, click)
, actionTypes.UPDATE_CATEGORIES_SUCCESS
不會被我的減速器捕獲:
import * as actionTypes from '../actions/actionTypes';
import initialState from './initialState';
export default function dashboardReducer(state = initialState.dashboard, action) {
switch(action.type) {
case actionTypes.UPDATE_CATEGORIES_SUCCESS:
return Object.assign({}, state, {categories: action.categories});
default:
return state;
}
}
我假設這是因為當我嘗試執行此操作時,收到錯誤消息:
2 Uncaught Error: A state mutation was detected between dispatches, in the path `dashboard.categories.0.onClick`. This may cause incorrect behavior. (http://redux.js.org/docs/Troubleshooting.html#never-mutate-reducer-arguments)
我在updateMenuOnAll導出的函數中是否做錯了導致這種狀態突變的事情? 我認為使用Object.assign()
可以避免此問題。 謝謝!
編輯
當單擊適當的div時,以下react組件是一個調用categoryAllClick
:
import React from 'react';
import PropTypes from 'prop-types';
import {connect} from 'react-redux';
import {bindActionCreators} from 'redux';
import * as dashboardActions from '../../../../../actions/dashboardActions';
class CheckboxItem extends React.Component {
constructor() {
super();
this.handleClick = this.handleClick.bind(this);
}
handleClick() {
const {menu, title, type, categoryAllClick, tagAllClick, actions} = this.props;
if (type === "categories") {
if (title === "all") {
actions.categoryAllClick(menu, !categoryAllClick);
} else {
actions.updateCategories(title, menu);
}
} else if (type === "tags") {
if (title === "all") {
actions.tagAllClick(menu, !tagAllClick);
} else {
actions.updateTags(title, menu);
}
}
}
render() {
return (
<div className="div-common-menu-item" onClick={this.handleClick}>
// Child componenets here
</div>
);
}
}
CheckboxItem.propTypes = {
menu: PropTypes.array.isRequired,
title: PropTypes.string.isRequired,
type: PropTypes.string.isRequired,
categories: PropTypes.array.isRequired,
tags: PropTypes.array.isRequired,
categoryAllClick: PropTypes.bool.isRequired,
tagAllClick: PropTypes.bool.isRequired,
actions: PropTypes.object.isRequired
};
function mapStateToProps(state) {
return {
categories: state.dashboard.categories,
tags: state.dashboard.tags,
categoryAllClick: state.dashboard.categoryAllClick,
tagAllClick: state.dashboard.tagAllClick
};
}
function mapDispatchToProps(dispatch) {
return {
actions: bindActionCreators(dashboardActions, dispatch)
};
}
const connectedStateAndProps = connect(mapStateToProps, mapDispatchToProps);
export default connectedStateAndProps(CheckboxItem);
您的updateMenuOnAll
函數有以下三種錯誤:
map()
返回一個新數組,但是您忽略了該返回值 Object.assign()
不是復制數組的正確方法。 更好的方法是:
export function updateMenuOnAll(menu, click) {
const newOnClick = !!click;
const finalMenu = menu.map(item => ({...item, onClick : newOnClick}));
return finalMenu;
}
我沒有在函數“ Utils.updateMenuOnAll”中看到您的代碼,但是如果它正在更改您的對象類別,則可能會看到該錯誤。
這是因為您不應直接調用categoryAllClick(categories, click)
,而應使用調度程序。 例如,如果您有反應,則使用react-redux
“連接”組件(使用import { connect } from 'react-redux';
)在mapDispatchToProps
參數中傳遞函數。
話雖如此,您正確地假設使用Object.assign
不會改變您的狀態。
問題是updateMenuOnAll
函數。 將其重寫為以下內容可解決此問題。 感謝大家!
export function updateMenuOnAll(menu, click) {
return menu.map(item => ({title: item.title, onClick: click}));
}
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