React Native infinite loop-CodePudding

I declared and initialized the variable like this:

const [user, setUser] = useState(null)

Then make a function like this:

const getUser2 = async () => {
    try {
      const user2 = await AsyncStorage.getItem('user')
      let parsed = JSON.parse(user2)
      setUser(parsed)
      console.warn('1')
    } catch(err) {}
}

Then call it like this:

useEffect(() => {
    getUser2()
    return () => getUser2()
})

The problem is when I run it, it produces an infinite loop like this:

Why does it loop infinitely?

CodePudding user response：

Add dependency array, Then it will get called only once -

useEffect(() => {
    getUser2()
    return () => getUser2()
}, [])

Go through this reference for better understanding of useEffect - https://blog.logrocket.com/guide-to-react-useeffect-hook/

In your useEffect you haven't added any dependency array, so on each re-render this useEffect is getting called, when you add [ ] dependency as a parameter to useEffect then it will act as componentDidMount which get called only once.

CodePudding user response：

useEffect will be triggered every time the setState is set, if you do not pass the second parameter