Challenge Solution in "Updating Arrays in State" Page Uses Mutation

For the solution to the third challenge in the Updating Arrays in State page, it uses the following function:

function handleAddTodo(title) {
  setTodos([
    ...todos,
    {
      id: nextId++,
      title: title,
      done: false
    }
  ]);
}

This changes nextId, a variable outside the component's scope, which I believe is a mutation. It should instead use the length of todos to set the next id.

從連結的「Updating Arrays in State」頁面開始，檢查第三個挑戰的解法，特別是 handleAddTodo 函式及其對 nextId 的使用方式。更新範例，使其不會變更元件外部的變數，然後確認挑戰的解法仍會產生預期的 todo ID。