[SOLVED] React TypeScript 16.8 How to make useEffect() async

React TypeScript 16.8 How to make useEffect() async

Why can't useEffect() use async-await?

const Home: React.FC = () => {
    
    useEffect(async () => {
        console.log(await ecc.randomKey())
    }, [])
    
    return (
    ...

The error I get is

Argument of type '() => Promise' is not assignable to parameter of type 'EffectCallback'.

Type 'Promise' is not assignable to type 'void | (() => void | undefined)'.

Type 'Promise' is not assignable to type '() => void | undefined'.

Type 'Promise' provides no match for the signature '(): void | undefined'.ts(2345)

Solution

Declaring the effect as async function is not recommended. But you can call async functions within the effect like following:

useEffect(() => {
  const genRandomKey = async () => {
    console.log(await ecc.randomKey())
  };

  genRandomKey();
}, []);