Changelog for #2212

Undefined check for object descriptor

changelog.txt

@@ -13,7 +13,7 @@ OPENSEADRAGON CHANGELOG
 * Fixed: Cropping tiled images with polygons was broken (#2183 @altert)
 * Fixed: Disabling buttons only changed their appearance, but they were still clickable (#2187 @pearcetm)
 * Fixed: ImageTileSource produced an error having to do with getTileHashKey (#2190 @Aiosa)
-* Fixed: On startup you would get an unnecessary "Viewer.buttons is deprecated" warning (#2201 @joedf, #2219 @jssullivan)
+* Fixed: On startup you would get an unnecessary "Viewer.buttons is deprecated" warning (#2201 @joedf, #2219 @jssullivan, #2212 @joedf)
 
 3.1.0:
 

src/openseadragon.js

@@ -1102,13 +1102,19 @@ function OpenSeadragon( options ){
                 // Extend the base object
                 for ( name in options ) {
                     var descriptor = Object.getOwnPropertyDescriptor(options, name);
-                    if (descriptor.get || descriptor.set) {
-                        Object.defineProperty(target, name, descriptor);
+
+                    if (descriptor !== undefined) {
+                        if (descriptor.get || descriptor.set) {
+                            Object.defineProperty(target, name, descriptor);
+                            continue;
+                        }
+
+                        copy = descriptor.value;
+                    } else {
+                        $.console.warn('Could not copy inherited property "' + name + '".');
                         continue;
                     }
 
-                    copy = descriptor.value;
-
                     // Prevent never-ending loop
                     if ( target === copy ) {
                         continue;