使用Redux防止重复的最佳做法是什么？

Question

如果你正在使用Redux，并且你有一个处于状态的数组，但你想防止重复的项目进入该数组，你应该防止重复项添加到reducer中的数组中， 还是应该这样做在动作创作者？

Answer 1

Generally, Redux action creators should avoid knowing anything about the application state, as the author of Redux, Dan Abramov, describes :

In general accessing state in action creators is an anti-pattern and you should avoid this when possible.

The best practices for Redux dictate that action creators just create an action to represent that something happened, without considering how that will affect the state. In other words, an action means 'something happened', not 'the state needs to be changed'; it's fine to completely ignore an action if it's not relevant.

On the other hand, a reducer is specifically intended to be a pure function of the previous state and the action, so it is perfectly placed to judge whether an action requires state mutation.

So, in summary, the reducer is probably the best choice, so your action creators can remain 'thin'.