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JavaScript Asynchronous Programming with JavaScript Understanding Promises Using Fetch

Fradely Dilone
Fradely Dilone
24,037 Points

const wikiUrl = 'https://en.wikipedia.org/api/rest_v1/page/summary/'; Nothing is working

Phil Wright
Phil Wright
3,654 Points

Hi Fradely.

How is it not working? That assigns correctly, see output from console below:

const wikiUrl = 'https://en.wikipedia.org/api/rest_v1/page/summary/';

What are you trying to do, and what are you expecting to happen?


4 Answers

The current problem appears to be that api-open-notify and Wikipedia disagree on how to spell the name of one of the Russian astronauts, so the two data sources aren't matching up. Wikipedia is spelling the name as Anatoli Ivanishin, while api-open-notify is spelling it Anatoly Ivanishin, with the difference being the last letter of the first name. I don't know how to make the code account for this issue, but maybe someone else does.

The following code works for me. Hope it helps. Adding a bit of error handling so that information for the rest of the astronauts can be displayed.

First, in getProfiles function, I changed Promise.all() to Promise.allSettled(). Promise.all() needs all promises to be fulfilled, while Promise.allSettled() can have rejects. See MDN reference here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all

Second, in generateHTML function, I added a error handling to ensure person.value.type === "standard", otherwise don't do anything for that iteration. This ensures any names not found in Wikipedia can be skipped.

const astrosUrl = 'http://api.open-notify.org/astros.json';
const wikiUrl = 'https://en.wikipedia.org/api/rest_v1/page/summary/';
const peopleList = document.getElementById('people');
const btn = document.querySelector('button');

function getProfiles(json) {
  const profiles = json.people.map( person => {
    return fetch(wikiUrl + person.name)
            .then (response => response.json())
            .catch (err => console.log('Error fetching Wikipedia:', err));      
  return Promise.allSettled(profiles);

function generateHTML(data) {
  data.map( person => {
    const section = document.createElement('section');
    if (person.value.type === "standard") {
      section.innerHTML = `
        <img src=${person.value.thumbnail.source}>


btn.addEventListener('click', (event) => {
  event.target.textContent = 'Loading...';
    .then (response => response.json())
    .catch( err => {
      peopleList.innerHTML = '<h3>Something went wrong</h3>';
    .finally(() => event.target.remove());


That worked for me too, but only displaying the pictures and the sections. The text is all "undefined".

Jonathan Drake
Jonathan Drake
Full Stack JavaScript Techdegree Student 11,668 Points

Same issue...current problem is Sergey Korsakov comes back on the JSON data as "Sergey Korsakov." The period at the end of his name screws up the url production in getProfiles. I resolved it specifically by using an if statement to catch the period and change the value of person.name to the name without the period.

This appears to be a common problem in this course, and the AJAX request returns with a 404 error (Source not found), because it is looking for the wrong name. Sadly, the only real way of fixing this in the code, is to implement a manual fix;

    if (person.name != "yulia_pereslid"){ 
      return getJSON(wikiUrl + person.name);      
    } else {
      return getJSON(wikiUrl + "yulia_peresild"); 
  • Of course, by now, this name error is no longer relevant, as she isn't on the list anymore, but another set of names with problems of the same nature has most likely taken over.