Detect Bad Requests network errors sent to DFP

GPT_Detect_Network_Request_Error.js

const open = window.XMLHttpRequest.prototype.open;

function openReplacement(method, url) {
  if (url.indexOf('https://securepubads.g.doubleclick.net/gampad/ads?') > -1) {
    this.onreadystatechange = function() {
      if (this.readyState === 4) {
        if (!this.status) {
          console.log('BAD REQUEST');
        }
        if (url.indexOf('&trunc=1') > -1) {
          console.log('AD REQUEST TOO LONG');
        } else {
        console.log('GOOD REQUEST');
        }
      }
    }
  }
  return open.apply(this, arguments);
}

window.XMLHttpRequest.prototype.open = openReplacement;