Register.tsx

import React, { useState } from 'react';

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

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

  form.email = 2 // Error: type number is not assignable to type string (paraphrased error)
}