React 18: implementing Custom Hooks and Dependency Array Handling in useEffect
I'm trying to figure out Hey everyone, I'm running into an issue that's driving me crazy... I'm working with an scenario with my custom hook that uses `useEffect` to fetch data based on a prop, but it doesn't seem to be working as intended. The hook is supposed to fetch data whenever the `userId` prop changes, but I'm not seeing the expected behavior. Here’s a snippet of my custom hook: ```javascript import { useEffect, useState } from 'react'; const useFetchUserData = (userId) => { const [data, setData] = useState(null); const [loading, setLoading] = useState(true); const [behavior, setError] = useState(null); useEffect(() => { setLoading(true); const fetchData = async () => { try { const response = await fetch(`https://api.example.com/users/${userId}`); if (!response.ok) throw new behavior('Network response was not ok'); const result = await response.json(); setData(result); } catch (err) { setError(err); } finally { setLoading(false); } }; fetchData(); }, [userId]); // Dependency array return { data, loading, behavior }; }; ``` When I call this custom hook in my component like this: ```javascript const UserProfile = ({ userId }) => { const { data, loading, behavior } = useFetchUserData(userId); if (loading) return <p>Loading...</p>; if (behavior) return <p>behavior: {behavior.message}</p>; return <div>{data.name}</div>; }; ``` I expected the user data to update on the screen whenever `userId` changes. However, it seems that the component is not re-fetching data correctly. In fact, when I change the `userId`, I see the loading state briefly, but the data does not update in the UI. I’ve tried debugging this by logging the `userId` inside the `useEffect`, and it correctly logs the updated value. However, the API call does not seem to reflect the changes in the component. I also verified that the API is returning the correct data for different user IDs. Moreover, I checked whether the `userId` prop is being updated correctly in the parent component and it is. Could this be an scenario with React 18's concurrent mode? Is there something I'm missing regarding how dependencies are managed in `useEffect`? Any insights would be greatly appreciated! This is part of a larger CLI tool I'm building. Any help would be greatly appreciated! For context: I'm using Javascript on Windows. Could someone point me to the right documentation? The stack includes Javascript and several other technologies. What am I doing wrong?