Well, since the function is declared outside ofuseEffect, you will have to put it in the dependency array of the hook. But if the function isn't wrapped inuseCallback, it will update on every re-render, and thus
useEffect(() => { // Create an scoped async function in the hook // 注意如果函数没有使用组件内的任何值,可以把它提到组件外面去定义 // 下面代码可以提到外面,可以自由地在 effect 中使用,下面就不改啦 async function asyncFunction() { await requestData(); setData(data) } // Execute the creat...
正确使用 async 函数和 useEffect 是一个常见的问题,因为在 useEffect 中直接使用 async 函数会导致一些问题。这是因为 useEffect 函数本身不能直接返回 Promise。下面是一种正确使用 async 函数和 useEffect 的方法: 代码语言:txt 复制 import React, { useEffect } from 'react'; function MyComponent() { useEffe...
卸载的时候会通过函数组件对应的 fiber 获取 effect 链表,然后遍历链表,获取环链上的每一个节点,如果 destroy 不是 undefined 就执行,所以如果 useEffect 第一个参数传入 async, 那么这里的 destroy 就是一个 promise 对象,对象是不能执行的,所以报错。 functioncommitHookEffectListUnmount(tag, finishedWork) {varu...
useEffectis similar tocomponentDidMountandcomponentDidUpdate, so if you usesetStatehere then you need to restrict the code execution at some point when用作componentDidUpdate如下图: function Dashboard() { const [token, setToken] = useState(''); ...
useEffect(() => { (async function fn() { const response = await selectReceiveMaterialRecord({ billDetailId: billDetailId, }); form.setFieldsValue({ materielId: response.data?.materialName }); setMaterielId(response.data?.materialId); ...
在React Native中,Function组件是一种无状态组件,它是使用JavaScript函数定义的组件。ASYNC / AWAIT是一种用于处理异步操作的语法。 在React Native中,ASYNC / AWAIT可以用于处理异步操作,例如网络请求、读取本地数据等。通过在函数前面加上async关键字,可以将函数标记为异步函数。在异步函数内部,可以使用await关键字...
The API is the same as React'suseEffect(), except for some notable differences: The destroy function is passed as an optional second argument: useAsyncEffect(callback,dependencies?);useAsyncEffect(callback,onDestroy,dependencies?); The async callback will receive a single function to check wheth...
When you use useEffect, if you use async...await... in the callback function, the following error will be reported. Looking at the error report, we know that theeffect function should return a destroy function (effect: refers to the cleanup function returned by return). If the first para...
When rendering and testing a component with a useEffect that calls an async function that modifies the component's state, then an act() console error will be output when running tests. @testing-library/react version: 10.0.4 jest version:...