react hooks useEffect 取消 promise
cancel promise
https://github.com/facebook/react/issues/15006#issuecomment-543059930
https://react.docschina.org/docs/hooks-effect.html#需要清除的-effect
https://overreacted.io/zh-hans/a-complete-guide-to-useeffect/
清除的 effect & 取消订阅 & 取消 promise
bug
OK
const { adcode, regions = [] } = regionData;
const [regionName, setRegionName] = useState('全国');
const [tableData, setTableData] = useState(regions);
useEffect(() => {
let isSubscribed = true;
// getRegionName(adcode).then(setRegionName);
getRegionName(adcode).then(() => {
if(isSubscribed) {
return setRegionName;
}}
);
// 添加name字段
const promises = [];
regions.forEach(item => {
promises.push(
getRegionName(item.code)
.then(name => {item.name = name;})
// eslint-disable-next-line no-console
.catch(() => console.log('获取%s地名失败', item.code)),
);
});
// 后端传来部分区划代码是错误的，找不到对应地名，暂时先剔除
Promise
.all(promises)
.then(() => {
if(isSubscribed) {
return setTableData(regions.filter(({ name }) => !!name));
}
});
return () => isSubscribed = false;
}, [adcode, regionData, regions]);
https://juliangaramendy.dev/use-promise-subscription/
https://segmentfault.com/a/1190000018652589#articleHeader7
refs
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