title: React Redux adding extra field for action cause promise to return differently
body: <p>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</p>
  
  <pre><code>export function getList() {
      const FIELD = '/comics'
      let searchUrl = ROOT_URL + FIELD + '?ts=' + TS + '&amp;apikey=' + PUBLIC_KEY + '&amp;hash=' + HASH;
      const request = axios.get(searchUrl)
      return {
          type: FETCH_LIST, 
          payload: request,
      }
  }
  </code></pre>
  
  <p>and reducer looks like</p>
  
  <pre><code>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;
      }
  }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/eg7Yb.png" rel="noreferrer"><img src="https://i.stack.imgur.com/eg7Yb.png" alt="Good result"></a></p>
  
  <p>As you can see, the object returns fine and I can get my list via action.payload.data.data.results</p>
  
  <p>Note that I am using redux promise as my middleware to handle the promise.</p>
  
  <p>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</p>
  
  <pre><code>export function getComicList() {
      const FIELD = '/comics'
      let searchUrl = ROOT_URL + FIELD + '?ts=' + TS + '&amp;apikey=' + PUBLIC_KEY + '&amp;hash=' + HASH;
      const request = axios.get(searchUrl)
      return {
          type: FETCH_COMIC_LIST, 
          isLoading: true, 
          payload: request,
      }
  }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/wHRfR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/wHRfR.png" alt="isLoading added"></a></p>
  
  <p>Why is simply adding another variable causing this problem??</p>