[英]React redux not updating global state
我正在使用沒有鈎子的 Redux,並且所有這些似乎都完美地結合在一起,但是當我查看瀏覽器控制台 Redux 窗口時,我的狀態沒有改變。 所以基本上我有一個看起來像這樣的商店文件
import {createStore, applyMiddleware} from "redux";
import thunk from 'redux-thunk'
import {composeWithDevTools} from "redux-devtools-extension/developmentOnly";
import rootReducer from './reducers'
const middleware = [thunk]
const initialState = {}
const store = createStore(rootReducer, initialState,composeWithDevTools(applyMiddleware(...middleware)))
export default store
然后我有我的全局減速器文件
import {combineReducers} from "redux";
import searchReducer from './searchReducer'
export default combineReducers({
books: searchReducer
})
和 searchReducers 文件
import {SEARCH_BOOK, SET_INDEX,FETCH_BOOKS} from "../actions/types";
const initialState = {
query: '',
books: [],
loading: false,
book: []
}
export default function (state = initialState, action) {
switch (action.type) {
case 'SEARCH_BOOK':
return {
...state,
query:action.payload,
loading: false
}
case 'SET_INDEX':
return {
...state,
index:action.payload,
loading: false
}
case 'FETCH_BOOKS':
return {
...state,
index:state.index+40,
books:state.books.concat(action.payload),
loading: false
}
default:
return state
}
}
現在我只有你在這里看到的動作類型是那個動作
import {SEARCH_BOOK} from "./types";
export const searchBook = query => dispatch => {
dispatch ({
type:SEARCH_BOOK,
payload:query
})
}
export const fetchBooks = (query,index) => {
console.log(query)
axios
.get(`https://www.googleapis.com/books/v1/volumes?q=${query}&maxResults=40&orderBy=relevance&startIndex=${index}`)
.then(response =>{
return({
type: FETCH_BOOKS,
payload: response.data.items
})}
)
.catch(err => console.log(err));
};
所有這些都在應用程序中捆綁在一起,我在其中導入了包裝所有內容的提供程序。 問題來了。 我有一個搜索表單,應該在更改時更新全局狀態的查詢值
import React, { useState, useReducer} from "react";
import {useSelector, useDispatch} from 'react-redux'
import { Button, Container, Row, Col, Form, FormGroup, FormInput } from "shards-react";
import queryBuilder from "../js/helper";
import style from "./SearchForm/body.module.css";
import {searchBook, fetchBooks} from "../actions/SearchActions";
const initialState = {
title:'',
author:'',
publisher:''
}
function reducer(state,{ field, value }){
return {
...state,
[field]: value
}
}
function SearchForm() {
const index = useSelector(state => state.index)
const [state, dispatch] = useReducer(reducer, initialState);
const [query, setQuery] = useState('');
const disp = useDispatch();
const onChange = e => {
dispatch({ field: e.target.name, value: e.target.value })
}
const { title,author,publisher } = state;
const handleSubmit = e => {
e.preventDefault()
setQuery(queryBuilder(state))
disp(fetchBooks(query, 0))
}
return(
<div>
<Container className={style.FormContainer}>
<Form onSubmit={handleSubmit}>
<Row className={'topBar'}>
<Col>
<FormGroup>
<FormInput id={'bookTitle'} name={'title'} placeholder={'title'} value={title} onChange={onChange}/>
</FormGroup>
</Col>
<Col>
<FormGroup>
<FormInput id={'bookAuthor'} name={'author'} value={author} onChange={onChange} placeholder={'author'}/>
</FormGroup>
</Col>
<Col>
<FormGroup>
<FormInput id={'bookPublisher'} name={'publisher'} value={publisher} onChange={onChange}
placeholder={'publisher'}/>
</FormGroup>
</Col>
<Col>
<Button outline theme='primary' type={'submit'}>Submit</Button>
</Col>
</Row>
</Form>
</Container>
</div>
)
}
export default SearchForm
我不知道缺少什么。
編輯正如建議的那樣,我嘗試使用鈎子,現在一切都很好地捆綁在一起。 現在的問題是取書。 我更新了操作文件,以便您可以看到我添加的操作。 當我調度此操作時,我收到此錯誤
動作必須是普通對象。 使用自定義中間件進行異步操作
有誰知道如何解決這個問題?
我想你的錯誤可以解決為
export const fetchBooks =(query,index) => dispatch => {
console.log(query)
axios
.get(`https://www.googleapis.com/books/v1/volumes?q=${query}&maxResults=40&orderBy=relevance&startIndex=${index}`)
.then(response =>{
dispatch({
type: FETCH_BOOKS,
payload: response.data.items
})}
)
.catch(err => console.log(err));
};
看起來您在fetchBooks
函數中缺少return
值。 您沒有返回承諾,這意味着 thunk 中間件沒有收到承諾結果。
export const fetchBooks = (query,index) => {
console.log(query)
return axios
.get(`https://www.googleapis.com/books/v1/volumes?q=${query}&maxResults=40&orderBy=relevance&startIndex=${index}`)
.then(response =>{
return({
type: FETCH_BOOKS,
payload: response.data.items
})}
)
.catch(err => console.log(err));
};
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