export default function App() {
  const [user, setUser] = useReducer(
    (state: User, newState: Partial<User>) => ({ ...state, ...newState }),
    defaultUser
  );

  return (
    <div className="App">
      <h1>Hello CodeSandbox</h1>

      <div>
        <span>Update name: </span>
        <input
          type="text"
          value={user.name}
          onChange={(e) => setUser({ name: e.target.value })}
        />
      </div>

      <pre>{JSON.stringify(user, null, 2)}</pre>
    </div>
  );
}