dva.js的dispatch有回调吗？

Question

handleRequestOptions = (options, cd) => {
    this.props.dispatch({
        type: this.page.model + '/enums',
        payload: {
            ClassName: options.payload,
            objectName: options.objectName,
        }
    }, cd())
}

this.handleRequestOptions(options, _ => {
    ...
})

---

好像没作用啊？dva有这个设计吗？

Answer 1

Dva@2中dispatch添加了Promise.
如下：
(cd) => dispatch(...).then(() => cd());

Answer 2

如果在dva@1中要实现回掉可以用Promise实现：

new Promise((resolve) => {
    dispatch({
       type: 'model/fetch',
       payload: {
          resolve,
          id: userId,
       }
    })
}).then((res) => {
    console.log(res);
})

然后在model的effects中这样写:

...

*fetch({ payload }, { call }) {
  const { resolve } = payload;
  const { data } = yield call(services.fetch, payload);
  if (data.code === 0) {
    // 通过resolve返回数据，返回的数据将在Promise的then函数中获取到
    !!resolve && resolve(data.data);
}