[英]Warning: Can't perform a React state update on an unmounted component. useEffect cleanup function
[英]Getting 'Can't perform a React state update on an unmounted component' before useEffect cleanup function executes
在调用useEffect清理函数之前,我收到警告“无法对未安装的组件执行React状态更新”。
这段代码:
const [data, setData] = useState({});
useEffect(() => {
doFetch();
return () => { console.log('useEffect cleanup'); };
}, []);
const doFetch = async () => {
const response = await fetchAsync(...);
console.log('about to set state');
setData(response.data);
console.log('did set state');
};
生成控制台输出:
about to set state
Warning: Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in a useEffect cleanup function.
did set state
useEffect cleanup
我认为我的清理函数将在组件卸载之前执行,因此在警告之前执行,但它在警告之后执行。 因此,我无法通过正确取消异步任务(我已经尝试过)来获得警告。 如何让这个警告消失?
如果它有任何区别,则使用ReactDOM.render()和ReactDOM.unmountComponentAtNode()在组件测试中安装和卸载组件。 fetchAsync函数正在被删除
const stub = sinon.stub(..., fetchAsync);
stub.returns(Promise.resolve({status: 200, data: {});
使用useLayoutEffect
而不是useEffect
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