Question

我只想在错误状态下添加错误消息。但是，当发生错误时，setError不会更改，就不会添加错误消息。后端以json格式{“ error”：“ error message”}的形式给出错误消息，如果我在控制台日志中，该错误可以正常运行，但错误状态不会更新。

import { useState, useCallback, useRef, useEffect } from 'react';

export const useHttpClient = () => {
    const [ isLoading, setIsLoading ] = useState(false);
    const [ error, setError ] = useState();

    const activeHttpRequests = useRef([]);

    const sendRequest = useCallback(async (url, method = 'GET', body = null, headers = {}) => {
        setIsLoading(true);
        const httpAbortCtrl = new AbortController();
        activeHttpRequests.current.push(httpAbortCtrl);
         try {
            const response = await fetch(url, {
                method,
                body,
                headers,
                signal: httpAbortCtrl.signal
            });
            const responseData = await response.json();
            activeHttpRequests.current = activeHttpRequests.current.filter(
                reqCtrl => reqCtrl !== httpAbortCtrl
            );

            if(!response.ok) {
                throw new Error(responseData.error);
            }

            setIsLoading(false);
            return responseData;
        } catch (e) {
            setError(e.message);
            setIsLoading(false);
            throw e;
        }
    }, []);

     const clearError = () => {
         setError(null);
     };

    useEffect(() => {
        //this runs as cleanup function before next time useEffect run or also when an component use useEffect unmount
        return () => {
            activeHttpRequests.current.forEach(aboutCtr => aboutCtr.abort());
        }
    }, []);

     return { isLoading, error, sendRequest, clearError };
}

Answer 1

当您的后端使用JSON进行响应时，这意味着响应状态代码可能为200（成功）。这使“ response.ok”正确。

您将必须查看返回的JSON字符串以获取有效数据或错误消息。

setState回调后useState不会改变吗？

1 个答案: