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JavaScript Asynchronous Programming with JavaScript Understanding Promises Using Fetch

Samuel Kleos
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Samuel Kleos
Front End Web Development Techdegree Student 13,679 Points

When is the promise being created by fetch()?

Looking at the following line by line:

btn.addEventListener('click', (event) => {
    event.target.textContent = "Loading...";
    fetch(astrosUrl)
        .then(response => response.json())
                .then(getProfiles)
        .then(generateHTML)
        .finally(() => event.target.remove());
});

Is the promise object being created after you pass astrosUrl to fetch() or is it being created by the .json() method.

1 Answer

Steven Parker
Steven Parker
231,272 Points

The promise object is created immediately upon calling fetch, but at that time it will still be in a pending state. The .json() method is not called until later when the promise has been (successfully) resolved.