在 api 获取请求失败后重新调用 useEffect

Question

我正在执行 useEffect() 以使用 JSON 数据更新状态。但是，获取请求有时会失败，因此如果发生这种情况，我想重新执行 useEffect 钩子：

...
import React, {useState, useEffect} from 'react';
import {getJsonData} from './getJsonData';

const myApp = () => {
    var ErrorFetchedChecker = false;
    const [isLoading,setIsLoading] = useState(true);
    const [data,setData] = useState(null);

    const updateState = jsonData => {
      setIsloading(false);
      setData(jsonData);
    };

    useEffect(() => {
      //console.log('EXECUTING');
      getJsonData().then(
        data => updateState(data),
        error => {
          Alert.alert('DATA FETCHING ERROR !', 'Refreshing ?...');
          ErrorFetchedChecker = !ErrorFetchedChecker;
          //console.log('LOG__FROM_CountriesTable: Executed');
        },
      );
    }, [ErrorFetchedChecker]);//Shouldn't the change on this variable
                              //be enough to re-execute the hook ? 

    return (
      <View>
        <Text>{state.data.title}</Text>
        <Text>{data.data.completed}</Text>
      </View>
    );
}

这是 getJsonData() 函数以防万一：

export async function getJsonData() {
  try {
    let response = await fetch('https://jsonplaceholder.typicode.com/todos/1');
    let responseJson = await response.json();
    return responseJson;
  } catch (error) {
    throw error;
    // Also, is this the correct way to handle the error ?
    // As the Alert in useEffect goes off either ways.
    // If not, advise me on how the error should be handled.
  }
}

Answer 1

这将工作

const myApp = () => {
    const [errorFetchedChecker, setErrorFetchedChecker] = useState(false);
    const [isLoading,setIsLoading] = useState(true);
    const [data,setData] = useState(null);

    const updateState = jsonData => {
      setIsloading(false);
      setData(jsonData);
    };

    useEffect(() => {
      //console.log('EXECUTING');
      getJsonData().then(
        data => updateState(data),
        error => {
          Alert.alert('DATA FETCHING ERROR !', 'Refreshing ?...');
          setErrorFetchedChecker(c => !c);
          //console.log('LOG__FROM_CountriesTable: Executed');
        },
      );
    }, [errorFetchedChecker]);

    return (
      <View>
        <Text>{state.data.title}</Text>
        <Text>{data.data.completed}</Text>
      </View>
    );
}