React component implementation guide state as expected when using useEffect with dependencies
I'm prototyping a solution and I've searched everywhere and can't find a clear answer. I'm stuck on something that should probably be simple. I'm experiencing an scenario with my React component that fails to update its state correctly when the dependencies in the `useEffect` hook change. I have a functional component that fetches data from an API whenever a specific prop changes, but the state doesn't seem to reflect the new data after the first update. Here's a simplified version of my component: ```javascript import React, { useState, useEffect } from 'react'; const DataFetcher = ({ userId }) => { const [data, setData] = useState(null); useEffect(() => { const fetchData = async () => { const response = await fetch(`https://api.example.com/users/${userId}`); const result = await response.json(); setData(result); }; fetchData(); }, [userId]); return <div>{data ? data.name : 'Loading...'}</div>; }; ``` In this example, `userId` is a prop that changes based on user actions. However, when I update the `userId`, the component renders the old data until the fetch completes again. I confirmed that the `useEffect` is triggering on `userId` changes, but the `data` state does not update immediately as expected. I've also tried adding a console log inside the `useEffect` to see when it's firing: ```javascript useEffect(() => { console.log(`Fetching data for userId: ${userId}`); // ...fetchData logic }, [userId]); ``` The log correctly shows that the fetch function is being called with the new `userId`, but the displayed name in the component still shows the previous user's name until the fetch resolves. This is causing confusion as the user interface does not reflect the current state of the application promptly. I am using React 17.0.2 and have verified that there are no other components that might be interfering with the state updates. Am I missing something in terms of best practices with `useEffect` or state management? How can I ensure the UI reflects the changes immediately upon updating `userId`? My development environment is macOS. This is part of a larger application I'm building. Any help would be greatly appreciated! The stack includes Javascript and several other technologies.