React Redux示例有一个非纯函数。我以为还原剂必须是纯的?

have to be pure .

有一个例子(来自 this page ):

// redux/actions.js
import { ADD_TODO } from "./actionTypes";

let nextTodoId = 0;
export const addTodo = content => ({
  type: ADD_TODO,
  payload: {
    id: ++nextTodoId,
    content
  }
});

// ... other actions

那是不是意味着我必须忘记我所学到的一切?