AppWithDynamicTitle.js

function Todos({}) {
  // Create the state
  const [_todos, setTodos] = useState(0);
  
  return (
    <div className="todos">
      <Helmet>
    
        {/* Display the state as string */}
        <title>MyApp | Todos {_todos.toString()}</title>

      </Helmet>
      <h1>Todos</h1>

      {/* Add one each click */}
      <button onClick={() => setTodos(_todos + 1)}>Add todo</button>

      <Link to="/config">Config</Link>
    </div>
  );
}