main.js

// Legacy cm.e support
if (cm.e) {
  snippetNeedsUpdating = true;
  // Process queued errors
  for (var i=0; i < cm.e.length; i+=1) {
    cm.onerror.apply(this, cm.e[i]);
  }
  // Override push to immediately call onerror
  cm.e.push = function(message, file, line, column) {
    cm.onerror(message, file, line, column);
  };
}

snippet.js

window._crashmat = {
  key: "mj8c",
  // TODO: find a way to get the environment without using sencha,
  // otherwise we can't report errors during loading
  env: bp.config.Main.env,
  debug: true
};

(function(w, d, cm, woe) {
  w.onerror = function(e,f,l,c) {
    debugger;
    cm.e = cm.e || []; cm.e.push([e,f,l,c]);
    if (woe) woe(e,f,l,c);
  };
  var e = d.createElement('script');
  e.async = true;
  e.src = 'https://db2uk9yp28y61.cloudfront.net/';
  (d.head || d.getElementsByTagName('head')[0]).appendChild(e);
})(window, document, window._crashmat, window.onerror);