From 0354dd2c24f92ba436a62e096060a566747bb9bb Mon Sep 17 00:00:00 2001
From: paweldomas <pawel.domas@jitsi.org>
Date: Mon, 31 Oct 2016 10:44:50 -0500
Subject: [PATCH] feat(index.html): prevent from displaying broken page

The commit adds an error listener which will replace the document body
with an error message if any of the files required for the app to
be displayed correctly fails to load.
---
 index.html | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/index.html b/index.html
index 0b48e162c..d60b121d9 100644
--- a/index.html
+++ b/index.html
@@ -6,6 +6,37 @@
     <script>
         window.indexLoadedTime = window.performance.now();
         console.log("(TIME) index.html loaded:\t", indexLoadedTime);
+        // XXX the code below listeners for errors and displays an error message
+        // in the document body when any of the required files fails to load.
+        // The intention is to prevent from displaying broken page.
+        var criticalFiles = [
+            "config.js",
+            "utils.js",
+            "do_external_connect.js",
+            "interface_config.js",
+            "lib-jitsi-meet.min.js",
+            "app.bundle.min.js",
+            "all.css"
+        ];
+        var loadErrHandler = function(e) {
+            var target = e.target;
+            // Error on <script> and <link>(CSS)
+            // <script> will have .src and <link> .href
+            var fileRef = (target.src ? target.src : target.href);
+            if (("SCRIPT" === target.tagName || "LINK" === target.tagName)
+                && criticalFiles.some(
+                    function(file) { return fileRef.indexOf(file) !== -1 })) {
+                window.onload = function() {
+                    document.body.innerHTML
+                        = "The application failed to load, missing file: "
+                            + fileRef;
+                };
+                window.removeEventListener(
+                    'error', loadErrHandler, true /* capture phase */);
+            }
+        }
+        window.addEventListener(
+            'error', loadErrHandler, true /* capture phase type of listener */);
     </script>
     <script><!--#include virtual="/config.js" --></script><!-- adapt to your needs, i.e. set hosts and bosh path -->
     <script src="utils.js?v=1"></script>