JS Request queue

request-queue.js

var queue = [
  'https://peerj.com/articles/1.json',
  'https://peerj.com/articles/2.json',
  'https://peerj.com/articles/3.json',
];

var run = function() {
    var xhr = new XMLHttpRequest;
    xhr.open('GET', queue.shift());
    xhr.responseType = 'json';
    xhr.onload = function() {
        console.log(xhr.response);
    
        if (queue.length) {
            run();
        }
    }
    xhr.send();
}

run();