I'll create a form that validates an email address against a mock database. When a valid email is submitted, it will return the user's ID and name; otherwise, it will show an error message.

This implementation includes:

1. A clean form with email validation
2. A mock database with sample users
3. A server action that simulates checking if an email exists
4. Proper loading states and error handling
5. A nice UI to display the results

To test it, try these emails:

• Valid emails (will return user data):

  • john.doe@example.com
  • jane.smith@example.com
  • admin@company.com
  • test@test.com
• Any other email will return an error message

The form validates the email format client-side and then sends it to the server action, which checks if it exists in our mock database. If found, it returns the user's ID and name; otherwise, it returns an appropriate error message.