我得到TypeError：當我嘗試測試異步操作時，無法讀取未定義的屬性'then'

Question

我有一個問題，在reactjs中測試異步操作。 這裏是我的代碼：

export function fillStoryBoard(snippetsLink, channel, uniqueStoryObj, isUniqueStorySearch) { 

return function(dispatch){ 
     for (var i = 0; i < snippetsLink.length; i++) { 
      loadStorySnippet(channel, snippetsLink[i], (i + 1),dispatch); 
     } 
    } 
} 

function loadStorySnippet(channel,snippetsLink,indexValue,dispatch){ 
    return axios.get(ServiceUrls.prototype.getServicesDfltUrl()+snippetsLink) 
     .then(response => { 
      dispatch({ 
       type: "FILL_STORYBOARDS", 
       payload: { 
        "channelName": channel, 
        "storiesSnippet": response.data, 
        "order":indexValue 
       } 
      }); 
     }).catch(function(response){ 

    }); 
} 

所以我ASNC通話中未導出的函數和有調用一個for循環這個ASNC功能的功能。

現在，這裏是我的測試：

it('should dispatch type: FILL_STORYBOARDS with what is returned from server as a payload',() => { 
    nock(ServiceUrls.prototype.getServicesDfltUrl()) 
     .get('/snippet/111') 
     .reply(200, {"id":1,"headline":"", 
      "label":"Other", 
      "imgUrl":"", 
      "postDate":0}); 


    const expectedActions = [ 
     { "type": "FILL_STORYBOARDS","payload": { "channel": "", 
      "storiesSnippet": {"id":1,"headline":"", 
       "label":"Other","imgUrl":"" + 
       "", 
       "postDate":0}, 
      "order":1 } } 
    ] 
    const store = mockStore(); 
    return store.dispatch(fillStoryBoard(["snippet/111"], "")).then(() => { 
     expect(store.getActions()[0].type).to.equal(expectedActions[0].type); 
    }) 
}) 

現在的問題是，當運行測試，我得到：

TypeError: Cannot read property 'then' of undefined 

任何想法如何，我可以解決這個問題？

Answer 1

由fillStoryBoard返回的thunk函數不返回承諾，因此您不能將.then關閉。

嘗試這樣：

return function(dispatch){ 
    var promises = []; 
    for (var i = 0; i < snippetsLink.length; i++) { 
     promises.push(loadStorySnippet(channel, snippetsLink[i], (i + 1),dispatch)); 
    } 
    return Promise.all(promises); 
} 

編輯：

如果沒有循環，那麼你可能只是這樣做：

return function(dispatch){ 
    return loadStorySnippet(...your arguments here, dispatch)); 
}