CODEWITHSUNDEEP
javascriptember.jspromise
CORS noob
CORS noob

Reputation: 61

Ember chained promises

I have a problem that I know is not very challenging. But for some reason, I am having difficulty coming up with a good solution. I need to fetch data from a URL. The URL itself, however, is fetched from another end-point. So, first I fetch an object containing the URL from the server. Upon getting the URL, I access the fetched URL which finally gives me the data I need. The data contains further URLs which I eventually have to fetch. How do I fetch all these data from model hook of ember route? 

model(params) {
let futureData = new Ember.RSVP.Promise((resolve,reject) => {
api.ajaxGet(
  `${api.buildV3EnterpriseUrl('reports')}` + '/' + params.report_id
).then(function (successVal) {
  resolve(successVal);
}, function (error) {
  reject(error);

  });
});

futureData.then((success) => {
      return 
       api.xmlRequest('GET',success.aggregationUrls.elements[0].url);
   })

return Ember.RSVP.hash({
  reportData: futureData
});

}

Upvotes: 1

Views: 964

Answers (1)

Bergi
Bergi

Reputation: 664538

You only forgot one tiny bit:

reportData = futureData.then(…)

Calling then upon the futureData promise doesn't mutate it, it returns a new promise for the result of the callback. You were ignoring that return value.

Then, after also fixing the Promise constructor antipattern, it looks like this:

model(params) {
    const futureData = api.ajaxGet(`${api.buildV3EnterpriseUrl('reports')}/${params.report_id}`);

    const futureReportData = futureData.then(success => {
        return api.xmlRequest('GET',success.aggregationUrls.elements[0].url);
    });

    return Ember.RSVP.hash({
        reportData: futureReportData
    });
}

which could also be shortened to

model(params) {
    return api.ajaxGet(api.buildV3EnterpriseUrl('reports') + '/' + params.report_id)
    .then(success => api.xmlRequest('GET',success.aggregationUrls.elements[0].url))
    .then(reportData => ({reportData}));
}

Upvotes: 1

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