From 42f3a62cac345b4ffb5a6640d03ce35fd767c202 Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Fri, 12 May 2017 16:13:09 +0200
Subject: [PATCH] handle errors with XHR

---
 www/common/common-util.js | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/www/common/common-util.js b/www/common/common-util.js
index e62ed7016..bbd648f7c 100644
--- a/www/common/common-util.js
+++ b/www/common/common-util.js
@@ -90,11 +90,21 @@ define([], function () {
     };
 
     Util.fetch = function (src, cb) {
+        var done = false;
+        var CB = function (err, res) {
+            if (done) { return; }
+            done = true;
+            cb(err, res);
+        };
+
         var xhr = new XMLHttpRequest();
         xhr.open("GET", src, true);
         xhr.responseType = "arraybuffer";
         xhr.onload = function () {
-            return void cb(void 0, new Uint8Array(xhr.response));
+            return void CB(void 0, new Uint8Array(xhr.response));
+        };
+        xhr.onerror = function () {
+            CB('XHR_ERROR');
         };
         xhr.send(null);
     };