我正在使用'控制'组件(在组件中使用setState()
)并在尝试保存表单数据时间歇性地获取此错误。 UserForm
onSave
在下面的组件代码中回调saveUser
方法。
我已经查看了Redux文档,并且无法解决我修改状态导致标题错误的问题,具体是:{{1 }}
据我所知,只进行了本地修改,并且reducer返回了我添加了更改的全局状态的副本。我一定错过了什么,但是什么?
这是组件代码:
Uncaught Error: A state mutation was detected between dispatches, in the path 'users.2'. This may cause incorrect behavior.
这里是减速器:
import React, {PropTypes} from 'react';
import {connect} from 'react-redux';
import {bindActionCreators} from 'redux';
import * as userActions from '../../actions/userActions';
import UserForm from './UserForm';
export class ManageUserPage extends React.Component {
constructor(props, context) {
super(props, context);
this.state = {
user: Object.assign({}, this.props.user),
errors: {},
saving: false
};
this.updateUserState = this.updateUserState.bind(this);
this.saveUser = this.saveUser.bind(this);
}
componentWillReceiveProps(nextProps) {
if (this.props.user.id != nextProps.user.id) {
this.setState(
{
user: Object.assign({}, nextProps.user)
}
);
}
}
updateUserState(event) {
const field = event.target.name;
let user = Object.assign({}, this.state.user);
user[field] = event.target.value;
return this.setState({user: user});
}
userFormIsValid() {
let formIsValid = true;
let errors = {};
if (this.state.user.firstName.length < 3) {
errors.firstName = 'Name must be at least 3 characters.';
formIsValid = false;
}
this.setState({errors: errors});
return formIsValid;
}
saveUser(event) {
event.preventDefault();
if (!this.userFormIsValid()) {
return;
}
this.setState({saving: true});
this.props.actions
.saveUser(this.state.user)
.then(() => this.redirect())
.catch((error) => {
this.setState({saving: false});
});
}
redirect() {
this.setState({saving: false});
this.context.router.push('/users');
}
render() {
return (
<UserForm
onChange={this.updateUserState}
onSave={this.saveUser}
errors={this.state.errors}
user={this.state.user}
saving={this.state.saving}/>
);
}
}
ManageUserPage.propTypes = {
user: PropTypes.object.isRequired,
actions: PropTypes.object.isRequired
};
ManageUserPage.contextTypes = {
router: PropTypes.object
};
function getUserById(users, userId) {
const user = users.find(u => u.id === userId);
return user || null;
}
function mapStateToProps(state, ownProps) {
let user = {
id: '',
firstName: '',
lastName: ''
};
const userId = ownProps.params.id;
if (state.users.length && userId) {
user = getUserById(state.users, userId);
}
return {
user: user
};
}
function mapDispatchToProps(dispatch) {
return {
actions: bindActionCreators(userActions, dispatch)
};
}
export default connect(mapStateToProps, mapDispatchToProps)(ManageUserPage);
以下是行动:
import * as types from '../actions/actionTypes';
import initialState from './initialState';
export default(state = initialState.users, action) =>
{
switch (action.type) {
case types.CREATE_USER_SUCCESS:
return [
// grab our state, then add our new user in
...state,
Object.assign({}, action.user)
];
case types.UPDATE_USER_SUCCESS:
return [
// filter out THIS user from our copy of the state, then add our updated user in
...state.filter(user => user.id !== action.user.id),
Object.assign({}, action.user)
];
default:
return state;
}
};
这是模拟API层:
import * as types from './actionTypes';
import userApi from '../api/mockUserApi';
import {beginAjaxCall, ajaxCallError} from './ajaxStatusActions';
export function createUserSuccess(user) {
return {type: types.CREATE_USER_SUCCESS, user};
}
export function updateUserSuccess(user) {
return {type: types.UPDATE_USER_SUCCESS, user};
}
export function saveUser(user) {
return function (dispatch, getState) {
dispatch(beginAjaxCall());
return userApi.saveUser(user)
.then(savedUser => {
user.id
? dispatch(updateUserSuccess(savedUser))
: dispatch(createUserSuccess(savedUser));
}).catch(error => {
dispatch(ajaxCallError(error));
throw(error);
});
};
}
答案 0 :(得分:13)
.c
是DOM中的顶级组件,但另一个名为ManageUserPage
的路由上的另一个组件正在其render方法中改变状态。
最初渲染方法如下所示:
UsersPage
我将render() {
const users = this.props.users.sort(alphaSort);
return (
<div>
<h1>Users</h1>
<input type="submit"
value="Add User"
className="btn btn-primary"
onClick={this.redirectToAddUserPage}/>
<UserList
users={users}/>
</div>
);
}
作业更改为以下内容,问题已解决:
users
答案 1 :(得分:5)
The problem isn't in this component or the reducer. It's probably in the parent component, where you're probably assigning users[ix] = savedUser
somewhere, and the users array is ultimately the same array as the one in the state.
答案 2 :(得分:0)
通过遵循redux official docs上建议的任何更新模式,解决了状态突变的问题
我更喜欢在减速器中使用createReducer
,而在后台使用immer.produce:
import { createReducer } from 'redux-starter-kit'
const initialState = {
first: {
second: {
id1: { fourth: 'a' },
id2: { fourth: 'b' }
}
}
}
const reducer = createReducer(initialState, {
UPDATE_ITEM: (state, action) => {
state.first.second[action.someId].fourth = action.someValue
}
})