reactjs - 保证发货顺序

Question

我试图找出有关 redux reducer 的一些信息，但我认为术语可能会有所不同，因为这是 JavaScript。

假设有以下 reducer :

import {
  ONE,
  TWO,
  THREE
} from "../actions/types";

export default function reducer(state = { /* some init state here */ }, action) {
  switch (action.type) {
    case ONE: {
      // this case takes 500ms to finish
      return {...state }
    }
    case TWO: {
       // this case takes 200ms to finish
       return {...state }
    }
    case THREE: {
       // this case takes 100ms to finish
       return {...state }
    }
    default: {
       return {...state }
    }
};

如果我从一个 Action 中执行以下操作:

dispatch({type: ONE});
dispatch({type: TWO});
dispatch({type: THREE});

他们保证按那个顺序解决吗？意思是，状态是同步的还是“单线程的”？或者会 case TWO: {}例如，在 case ONE: {} 之前触发完全的？

Answer 1

dispatch默认情况下是同步的，因此，只要您在 Action 创建者中没有异步调用，它们就会按照声明的顺序执行。

在 redux's docs暗示dispatch()是同步的:

Action creators can also be asynchronous and have side-effects. You can read about async actions in the advanced tutorial to learn how to handle AJAX responses and compose action creators into async control flow.