JavaScript Asynchronous Programming with JavaScript Understanding Promises From Callbacks to Promises

Uncaught Type Error and Uncaught reference error when making Promises

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I get errors on line 44 and line 12. Uncaught type error and uncaughtReferenceError. If you could explain the error in terms of the process of how a Promise operates that'd be great! This is my first JS course so I'm drinking from a firehose!!

1 Answer

Colton Shaw
Colton Shaw
11,929 Points

Jonathan Ambriz, You were very close it looks like you may have just not one Promise call and a >. See below!

function getJSON(url) {
  return new Promise ((resolve,reject) => { //this was not declared which means the entire promise structure created would not work.
    const xhr = new XMLHttpRequest();'GET', url);
    xhr.onload = () => {
      if(xhr.status === 200) {
        let data = JSON.parse(xhr.responseText);
      }else {
        reject( Error(xhr.statusText) );
    xhr.onerror = () => reject( Error('A network error occured.') );

btn.addEventListener('click', (event) => {
    .then(data => console.log(data))
    .catch(err => console.log(err)) //You were missing a > right here which is why this failed.;