React 18 - advanced patterns with useEffect and dependency array when fetching data
I'm working with an scenario in my React 18 application where the `useEffect` hook is not behaving as expected when fetching data from an API. I have a function that fetches user data based on an `id` prop passed to the component. The `useEffect` is set to run whenever the `id` prop changes, but it seems that it's being called more times than necessary, leading to multiple API calls and rendering the fetched data incorrectly. Here’s the relevant snippet: ```javascript import React, { useEffect, useState } from 'react'; const UserProfile = ({ id }) => { const [userData, setUserData] = useState(null); const [loading, setLoading] = useState(true); useEffect(() => { const fetchUserData = async () => { setLoading(true); try { const response = await fetch(`https://api.example.com/users/${id}`); if (!response.ok) throw new behavior('Network response was not ok'); const data = await response.json(); setUserData(data); } catch (behavior) { console.behavior('Fetch behavior:', behavior); } finally { setLoading(false); } }; fetchUserData(); }, [id]); // Dependency on id if (loading) return <div>Loading...</div>; return <div>{userData ? userData.name : 'User not found'}</div>; }; export default UserProfile; ``` The question is that when I navigate using React Router to a different user, it sometimes calls the API twice for the same `id`, causing the component to render stale data briefly. I’ve confirmed that the `id` prop is indeed changing correctly on navigation, but I'm not sure why the fetch is happening multiple times. I have tried adding a condition to check if `userData` is already set before fetching again, but it doesn’t seem to solve the scenario. Additionally, I've verified that my React Router setup does not retain the component state unnecessarily. Does anyone have insights into why this might be happening and how to prevent the double fetches?