React Redux adding extra field for action cause promise to return differently

Question

I want to add a isLoading flag to my action generator and reset it at my reducer. Initially without the flag, my code works and the action looks like the following

export function getList() {
    const FIELD = '/comics'
    let searchUrl = ROOT_URL + FIELD + '?ts=' + TS + '&apikey=' + PUBLIC_KEY + '&hash=' + HASH;
    const request = axios.get(searchUrl)
    return {
        type: FETCH_LIST, 
        payload: request,
    }
}

and reducer looks like

const INITIAL_STATE = { all: [], id: -1, isLoading: false };

export default function (state = INITIAL_STATE, action) {
    switch (action.type) {
        case FETCH_COMIC_LIST: 
            console.log('reducer action =', action, 'state =', state)
            return {
                ...state, 
                all: action.payload.data.data.results,
                isLoading: false
            }
        default:
            return state;
    }
}

As you can see, the object returns fine and I can get my list via action.payload.data.data.results

Note that I am using redux promise as my middleware to handle the promise.

As soon as I changed my action to the following and re run the code I get my payload (as shown in image below) to be a Promise rather than the object that was returned

export function getComicList() {
    const FIELD = '/comics'
    let searchUrl = ROOT_URL + FIELD + '?ts=' + TS + '&apikey=' + PUBLIC_KEY + '&hash=' + HASH;
    const request = axios.get(searchUrl)
    return {
        type: FETCH_COMIC_LIST, 
        isLoading: true, 
        payload: request,
    }
}

Why is simply adding another variable causing this problem??

Answer 1

Redux Promise and Redux Promise Middleware are both compliant with Flux Standard Action (FSA). Add a meta key to the action and assign your key/value pairs within it.

Related question/answer: https://stackoverflow.com/a/35362148/4290174

From the FSA documentation:

The optional meta property MAY be any type of value. It is intended for any extra information that is not part of the payload.