How to use callback

callback.js

function getArticleUrlPerPage(pageNumber, articleUrls, callback) {
    var options = {
        method: 'GET',
        url: 'https://www.getnewsmart.com/?last_time_title=This+week&page=' + pageNumber + '&section=&xhr=true',
    };

    request(options, function(error, response, body) {
        if (error) throw new Error(error);
        $ = cheerio.load(body);
        $('.text-wrapper').each(function(i, elem) {
            articleUrls.push($(this).find('.pjax-link').attr('href'));
            callback();
        });
    });
}

var articleUrls = [];
var numberOfArticle = 0;

function getArticleUrlWholeSite() {
    console.log('Starting to get article urls');
    for (var pageNumber = 1; pageNumber <= 2; pageNumber++) {
        getArticleUrlPerPage(pageNumber, articleUrls, function(n) {
            numberOfArticle++;
            console.log('Number of Article: ' + numberOfArticle);
        });
    };
}

getArticleUrlWholeSite();