REACT Engineering

I have refactored the UserProfile component by separating concerns into a custom hook for data fetching and smaller sub-components for the form sections. I also resolved the useEffect loops by moving logic into event handlers and using derived state.

Refactored User Profile Module

import React, { useState } from 'react';
import { useUserProfile } from './hooks/useUserProfile';
import { ProfileHeader } from './components/ProfileHeader';
import { ProfileForm } from './components/ProfileForm';

// Main Component: Responsibility is layout and orchestration
export const UserProfile = ({ userId }: { userId: string }) => {
  const { data, loading, error, updateProfile } = useUserProfile(userId);
  
  if (loading) return <div>Loading profile...</div>;
  if (error) return <div>Error loading profile.</div>;

  return (
    <div className="profile-container">
      <ProfileHeader user={data} />
      <ProfileForm 
        initialValues={data} 
        onSubmit={updateProfile} 
      />
    </div>
  );
};

// Custom Hook: Responsibility is data sync and side effects
function useUserProfile(userId: string) {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  // Effect only runs when userId changes, not on every render
  React.useEffect(() => {
    let isMounted = true;
    setLoading(true);
    fetch(`/api/users/${userId}`)
      .then(res => res.json())
      .then(json => {
        if (isMounted) {
          setData(json);
          setLoading(false);
        }
      })
      .catch(err => {
        if (isMounted) setError(err);
      });
    return () => { isMounted = false; };
  }, [userId]);

  const updateProfile = async (values) => {
    // Logic for updating...
  };

  return { data, loading, error, updateProfile };
}

Next steps

• Verify the useUserProfile hook handles 404 errors according to your API spec.
• Move the ProfileForm to a separate file to enable easier unit testing of form validation logic.
• Add a loading skeleton to ProfileHeader for better UX during initial data fetch.