Register.tsx

import React, { useState } from 'react';

interface FormState {
  email: string;
  password: string;
  passwordConfirm: string;
}

const initialFormState: FormState = {
  email: '',
  password: '',
  passwordConfirm: ''
}

const Register: React.FC = (): JSX.Element => {
  const [form, setForm] = useState<FormState>(initialFormState)
  
  ...
}