javascript - Redux thunk : return promise from dispatched action

Question

是否可以从 action creator 返回 promise/signal，当 Redux thunk 成功派发特定 action 时解决？

考虑这个 Action 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 已分派(dispatch) POST_SUCCESS 或 POST_ERROR 操作时，我想在调用 doPost 操作创建器之后异步调用组件中的某些函数。一种解决方案是将回调传递给 action creator 本身，但这会使代码变得困惑并且难以掌握和维护。我也可以在 while 循环中轮询 Redux 状态，但那样效率很低。

理想情况下，解决方案应该是一个 promise ，它应该在某些操作(在本例中为 POST_SUCCESS 或 POST_ERROR)被调度时解决/拒绝。

handlerFunction {
  doPost(data)
  closeWindow()
}

上面的例子应该重构，所以只有在 doPost() 成功时才调用 closeWindow()。

Answer 1

当然，您可以从异步操作返回 promise :

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 函数返回一个 promise:

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.
      });
}