From 5849c0631435b89bb1abd584d67015b27e8a1ec0 Mon Sep 17 00:00:00 2001
From: Johannes Meyer <johannes.meyer@icinga.com>
Date: Tue, 30 Jul 2019 08:17:29 +0200
Subject: [PATCH] storage.js: Don't try and allow to register events for
 non-local backends

---
 public/js/icinga/storage.js | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/public/js/icinga/storage.js b/public/js/icinga/storage.js
index 8cdabb86f..c48aea522 100644
--- a/public/js/icinga/storage.js
+++ b/public/js/icinga/storage.js
@@ -171,6 +171,10 @@
          * @returns {void}
          */
         onChange: function(key, callback, context) {
+            if (this.backend !== window.localStorage) {
+                throw new Error('[Storage] Only the localStorage emits events');
+            }
+
             var prefixedKey = this.prefixKey(key);
 
             if (typeof Icinga.Storage.subscribers[prefixedKey] === 'undefined') {
@@ -273,7 +277,10 @@
             this.storage = storage;
             this.key = key;
 
-            storage.onChange(key, this.onChange, this);
+            if (storage.backend === window.localStorage) {
+                storage.onChange(key, this.onChange, this);
+            }
+
             return this;
         },