Fix feedback loop between L.hash and popstate

diff --git a/app/assets/javascripts/index.js b/app/assets/javascripts/index.js
index c6295cb10bb8dfc08e9cf97ac328a1c3d8a5d995..3db9d7ba0a56eefac958c0c4f8112bad605ff7f0 100644 (file)
--- a/app/assets/javascripts/index.js
+++ b/app/assets/javascripts/index.js
@@ -24,8 +24,12 @@ $(document).ready(function () {
 
   map.hash = L.hash(map);
 
-  $(window).on('popstate', function() {
-    map.hash.update();
+  $(window).on('popstate', function(e) {
+    // popstate is triggered when the hash changes as well as on actual navigation
+    // events. We want to update the hash on the latter and not the former.
+    if (e.originalEvent.state) {
+      map.hash.update();
+    }
   });
 
   var copyright = I18n.t('javascripts.map.copyright', {copyright_url: '/copyright'});