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();
Warning: useEffect function must return a cleanup function or nothing. Promises and useEffect(async () => …) are not supported, but you can call an async function inside an effect 这就是为什么不能直接在useEffect中使用async函数, 因此,我们可以不直接调用async函数,而是像下面这样: function App() ...
但是,useEffect 不应该返回任何内容。所以你会在控制台日志中看到以下警告: Warning: An effect function must not return anything besides a function, which is used for clean-up. It looks like you wrote useEffect(async () => ...) or returned a Promise. Instead, write the async function inside y...
Write the asynchronous function inside theuseEffect Usually the solution is to simply write the data fetching code inside theuseEffectitself, like so: ···useEffect(()=>{// declare the data fetching functionconstfetchData=async()=>{constdata=awaitfetch('https://yourapi.com');}// call the ...
or returned a Promise...Instead, write the async function inside your effect and call it immediately: 这就是为什么不能直接在 useEffect 中使用...async 函数的原因。...因此,我们可以不直接在 useEffect 里使用用 async 函数,需要把函数提取出来,像下面这样: import React, { useState, useEffect } from...
useEffect(() => { // React advises to declare the async function directly inside useEffect async function getToken() { const headers = { Authorization: authProps.idToken // using Cognito authorizer }; const response = await axios.post( ...
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:...
useEffect(() => { (async function fn() { const response = await selectReceiveMaterialRecord({ billDetailId: billDetailId, }); form.setFieldsValue({ materielId: response.data?.materialName }); setMaterielId(response.data?.materialId); ...
Approach 1: Create an asynchronous function (async...await method), and then execute the function. useEffect(() => { const asyncFun = async () => { setPass(await mockCheck()); }; asyncFun(); }, []); Approach 2: You can also use IIFE, as follows: ...
effect: A function that returns a promise. The function receives anAsyncEffectStatusobject. deps: An optional array of dependencies, just like withuseEffect. AsyncEffectStatus An object with the following properties: active: A boolean indicating if the cycle the effect was run in is still active...