Question

是否可以从动作创建者返回promise / signal，当Redux thunk成功发送某些动作时解决？

考虑这个动作创建者：

function doPost(data) {
    return (dispatch) => {
        dispatch({type: POST_LOADING});
        Source.doPost() // async http operation
            .then(response => {
                dispatch({type: POST_SUCCESS, payload: response})
            })
            .catch(errorMessage => {
                dispatch({type: POST_ERROR, payload: errorMessage})
            });
    }
}

当Redux调度POST_SUCCESS或POST_ERROR操作时，我想在调用 doPost 操作创建器后，在组件中异步调用某个函数。一种解决方案是将回调传递给动作创建者本身，但这会使代码变得混乱，难以掌握和维护。我也可以在while循环中轮询Redux状态，但这样效率很低。

理想情况下，解决方案是一个承诺，当某些操作（在本例中为POST_SUCCESS或POST_ERROR）被调度时，它应该解析/拒绝。

handlerFunction { doPost(data) closeWindow() }

上面的例子应该被重构，所以只有在doPost（）成功时才会调用closeWindow（）。

Answer 1

当然，您可以从异步操作返回承诺：

function doPost(data) {
    return (dispatch) => {
        dispatch({type: POST_LOADING});
        // Returning promise.
        return Source.doPost() // async http operation
            .then(response => {
                dispatch({type: POST_SUCCESS, payload: response})
                // Returning response, to be able to handle it after dispatching async action.
                return response;
            })
            .catch(errorMessage => {
                dispatch({type: POST_ERROR, payload: errorMessage})
                // Throwing an error, to be able handle errors later, in component.
                throw new Error(errorMessage)
            });
    }
}

现在，dispatch函数正在返回一个承诺：

handlerFunction {
  dispatch(doPost(data))
      // Now, we have access to `response` object, which we returned from promise in `doPost` action.
      .then(response => {
          // This function will be called when async action was succeeded.
          closeWindow();
      })
      .catch(() => {
          // This function will be called when async action was failed.
      });
}

Redux thunk：从派遣行动中返回承诺

1 个答案: