如何在 React 的 UseEffect() 中调用异步函数? [英] How to call an async function inside a UseEffect() in React?
问题描述
我想调用一个异步函数并获取我的 UseEffect 的结果.
我在网上找到的fetch api例子是直接在useEffect函数中制作的.如果我的 URL 发生变化,我必须修补我所有的提取.
当我尝试时,我收到一条错误消息.
这是我的代码.
<代码>异步函数 getData(userId) {const data = await axios.get(`http://url/api/data/${userId}`).then(承诺=> {返回promise.data;}).catch(e => {控制台错误(e);})返回数据;}功能blabla(){const [data, setData] = useState(null);useEffect(async() => {设置数据(获取数据(1))}, []);返回 (<div>这是{数据[名称"]}
);}
index.js:1375 警告:除了用于清理的函数之外,效果函数不得返回任何内容.看起来你写了 useEffect(async () => ...) 或者返回了一个 Promise.相反,在您的效果中编写异步函数并立即调用它:
useEffect(() => {异步函数 fetchData() {//你可以在这里等待const response = await MyAPI.getData(someId);//...}取数据();}, [someId]);//或者 [] 如果效果不需要道具或状态
在你的 effect 中创建一个异步函数,等待 getData(1)
结果然后调用 setData()
:
useEffect(() => {const fetchData = async() =>{const 数据 = 等待 getData(1);设置数据(数据);}取数据();}, []);
I would like to call an async function and get the result for my UseEffect.
The fetch api examples i found on the internet are directly made in the useEffect function. If my URL changes, i must patch all my fetchs.
When i tried, i got an error message.
This is my code.
async function getData(userId) {
const data = await axios.get(`http://url/api/data/${userId}`)
.then(promise => {
return promise.data;
})
.catch(e => {
console.error(e);
})
return data;
}
function blabla() {
const [data, setData] = useState(null);
useEffect(async () => {
setData(getData(1))
}, []);
return (
<div>
this is the {data["name"]}
</div>
);
}
index.js:1375 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 your effect and call it immediately:
useEffect(() => {
async function fetchData() {
// You can await here
const response = await MyAPI.getData(someId);
// ...
}
fetchData();
}, [someId]); // Or [] if effect doesn't need props or state
Create an async function inside your effect that wait the getData(1)
result then call setData()
:
useEffect(() => {
const fetchData = async () => {
const data = await getData(1);
setData(data);
}
fetchData();
}, []);
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