Why fetch returns promise pending?

Question

I am using fetch to get data but it keeps returning promise as pending. I've seen many posts regarding this issue and tried all the possibilities but didn't solve my issue. I wanted to know why the fetch returns promise as pending in brief what are the possible cases where fetch returns pending status?

My piece of code for reference:

fetch(res.url).then(function(u){ 
    return u.json();
})
.then(function(j) { 
    console.log(j); 
});

Answer 1

A fetch() is a network operation. To avoid hanging until we get a reply from the network, we defer it to the background and give ourselves the promise that it will complete eventually.

So fetch(url).then((data) => data.json()) means that we fetch the url, wait for data to come in, get the json representation of the data and wait for that too (data.json() is a promise too)

Until we get a result, the promise is in the pending state. The server hasn't replied to our request yet.

-- Reading the comments, it might be nice to add a error handler as that is why the current fetch is supposedly not doing anything: fetch().then((data) => data.json()).catch((error) => console.log(error))