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JavaScript Asynchronous Programming with JavaScript Asynchronous JavaScript with Callbacks Implement a Callback

Cheryl Oliver
Cheryl Oliver
21,676 Points

Cant get the files to work in MAMP

I am trying to get this work in MAMP but none of the changes I make seem to do anything.

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');

// Make an AJAX request
function getJSON(url, callback) {
  const xhr = new XMLHttpRequest();
  xhr.open('GET', url);
  xhr.onload = () => {
    if(xhr.status === 200) {
      let data = JSON.parse(xhr.responseText);
      return callback(data);

// Generate the markup for each profile
function generateHTML(data) {
  const section = document.createElement('section');
  section.innerHTML = `
    <img src=${data.thumbnail.source}>

btn.addEventListener('click', (event) => {
  getJSON(astrosUrl, (json) => {
    json.people.map( person => {
      getJSON(wikiUrl + person.name, generateHTML);


So you can see that I have put a console.log("data") in the addeventlistener function but nothing is appearing in the console. The astronauts are showing up on the page, 4 out of the 6 are working and then I am getting an error for 2 saying that the data.thumbnail.source is undefined.

Am I doing something silly? I am very confused!

1 Answer

charlie g
charlie g
12,417 Points

Hi Cheryl! Check this, I had the same problem.

Cheryl Oliver
Cheryl Oliver
21,676 Points

Thanks Charlie, i had a look through those answers and picked the best solution for me. The mamp issue I was having was just a caching problem luckily so thats all fixed now as well :)