redux-当一个资源依赖另一个时，如何适当地更新它们

Question

Say I have a redux state tree like this:

{
  user: null,
  purchases: [],
}

The purchases belong to a user, so I always want to update the purchases when the user is updated (though purchases can be updated at other times, too).

How does one go about keeping the purchases up to date as the user changes? I could perhaps dispatch an update of the purchases inside the action creator for the update to the user, but then I foresee adding dispatches to the fetchUser action creator every time I add a resource that depends on the current user, which seems redundant.

The code for my current action creators is below (note that I use thunk middleware):

Action creators for fetching the user :

export const fetchUserSuccess = user => ({
  type: FETCH_USER_SUCCESS,
  user,
});

export const fetchUserFailure = () => ({
  type: FETCH_USER_FAILURE,
});

export const fetchUser = () => {
  return dispatch => {
    return getLoggedInUser(resp => {
      const { user } = resp;
      return (
        user
          ? dispatch(fetchUserSuccess(user))
          : dispatch(fetchUserFailure())
      );
    });
  }
};

Action creators for fetching the purchases :

export const fetchPurchasesSuccess = purchases => ({
  type: FETCH_PURCHASES_SUCCESS,
  purchases,
});

export const fetchPurchasesFailure = () => ({
  type: FETCH_PURCHASES_FAILURE,
});

export const fetchPurchases = user => {
  return dispatch => {
    return getPurchases(user, resp => {
      const { purchases } = resp;
      return (
        purchases
          ? dispatch(fetchPurchasesSuccess(purchases))
          : dispatch(fetchPurchasesFailure()));
    });
  }
};

Answer 1

Your purchases reducer could be 'listening' to some specific user's actions type like fe FETCH_USER_SUCCESS and then updating that resource directly in there.

Sorry for my English.

Answer 2

我认为您必须向用户传递购买详细信息。