Remove JSON Objects With Date Already Passed – Shopify

I think it would be easiest if you waited until you attached all of the metadata, and then once it is all completed, use articleArray.filter to take out the ones you don’t want. To do this, you have two options:

Option 1 – The Old Ways (setInterval)

Here, we keep count as the metadata is retrieved, and create an interval to check when they all have completed. Once done, a function is called (finish) that allows for continued processing.

var request = new XMLHttpRequest();

request.open('GET', '/admin/blogs/43130421348/articles.json');
request.responseType = 'json';
request.send();

request.onload = function () {
    var articleList = request.response;
    var articleArray = articleList.articles;
    var date = new Date();
    var ticks = Math.floor(date.getTime() / 1000);
    var count = 0;  //to keep track of how many metafields have been retrieved
    var checkInterval = null;

    articleArray.forEach(function (entry, index) {
        var metaRequest = new XMLHttpRequest();
        metaRequest.open('GET', '/admin/blogs/43130421348/articles/' + entry.id + '/metafields.json');
        metaRequest.responseType = 'json';
        metaRequest.send();
        console.log(index);

        metaRequest.onload = function () {
            var articleMetaObj = metaRequest.response;
            var articleMetaArr = articleMetaObj.metafields;
            entry.metafields = articleMetaArr;
            count++;
        };
    });

    //Function to continue processing
    var finish = function () {
        articleArray = articleArray.filter(a => new Date(a.metafields[0].value).getTime() < date.getTime());
        //Continue on...
    };

    //Wait until all metafields are retrieved to continue
    checkInterval = setInterval(function () {
        if (count === articleArray.length - 1) {
            clearInterval(checkInterval);
            finish();
        }
    }, 500);
};

Option 2 – The New Razmatazz (Promises & async/await)

Promises and async/await allow for writing some much nicer looking code when dealing with asynchronous operations.

If you feel like using these, I would suggest digging into the documentation to get more familiar, but here is what it could look like for your task.

//Functions that return Promises can be awaited...
var get = url => new Promise((resolve, reject) => {
    var request = new XMLHttpRequest();
    request.open('GET', url);
    request.responseType = 'json';
    //resolve is called when successful
    request.onload = () => resolve(request.response);
    //reject is called when there's a problem
    request.onerror = err => reject(err);
    request.send();
});

//await keyword must appear in an async function
var getArticles = async () => {
    var articleList = await get('/admin/blogs/43130421348/articles.json');
    return articleList.articles;
};

//Promise.all takes an array of promises and resolves when all of them are finished
//This lets you skip the messy setInterval stuff
var getArticleMetafields = async articles => {
    var requests = [];
    articles.forEach(a => {
        var url = '/admin/blogs/43130421348/articles/' + a.id + '/metafields.json';
        var promise = get(url);
        requests.push(promise);
    });
    var responses = await Promise.all(requests);
    responses.forEach((response, i) => {
        articles[i].metafields = response.metafields;
    });
    return articles;
};

//Notice the async on the handler
document.addEventListener('DOMContentLoaded', async () => {
    var articles = await getArticles();
    articles = await getArticleMetafields(articles);
    var date = new Date();
    articles = articles.filter(a => new Date(a.metafields[0].value) < date);
    //Continue...
});

Hope this helps. Cheers!