diff --git a/src/core/features/siteplugins/services/siteplugins-helper.ts b/src/core/features/siteplugins/services/siteplugins-helper.ts
index 2d674dac2..1c715bb6d 100644
--- a/src/core/features/siteplugins/services/siteplugins-helper.ts
+++ b/src/core/features/siteplugins/services/siteplugins-helper.ts
@@ -84,6 +84,7 @@ import { CoreSitePluginsWorkshopAssessmentStrategyHandler } from '../classes/han
 import { CoreContentLinksModuleIndexHandler } from '@features/contentlinks/classes/module-index-handler';
 import { CoreContentLinksDelegate } from '@features/contentlinks/services/contentlinks-delegate';
 import { CoreContentLinksModuleListHandler } from '@features/contentlinks/classes/module-list-handler';
+import { CoreObject } from '@singletons/object';
 
 const HANDLER_DISABLED = 'core_site_plugins_helper_handler_disabled';
 
@@ -615,9 +616,11 @@ export class CoreSitePluginsHelperProvider {
             if (result.jsResult) {
                 // Override default handler functions with the result of the method JS.
                 const jsResult = <Record<string, unknown>> result.jsResult;
-                for (const property in handler) {
-                    if (property != 'constructor' && typeof handler[property] == 'function' &&
-                            typeof jsResult[property] == 'function') {
+                const handlerProperties = CoreObject.getAllPropertyNames(handler);
+
+                for (const property of handlerProperties) {
+                    if (property !== 'constructor' && typeof handler[property] === 'function' &&
+                            typeof jsResult[property] === 'function') {
                         // eslint-disable-next-line @typescript-eslint/ban-types
                         handler[property] = (<Function> jsResult[property]).bind(handler);
                     }
diff --git a/src/core/singletons/object.ts b/src/core/singletons/object.ts
index b0dd856c3..9bc8fe760 100644
--- a/src/core/singletons/object.ts
+++ b/src/core/singletons/object.ts
@@ -36,6 +36,25 @@ export class CoreObject {
         return JSON.stringify(a) === JSON.stringify(b);
     }
 
+    /**
+     * Get all the properties names of an object, including the inherited ones except the ones from Object.prototype.
+     *
+     * @param object Object to get its properties.
+     * @return Set of property names.
+     */
+    static getAllPropertyNames(object: unknown): Set<string> {
+        if (typeof object !== 'object' || object === null || object === Object.prototype) {
+            // Not an object or we already reached root level.
+            return new Set<string>([]);
+        }
+
+        const properties = CoreObject.getAllPropertyNames(Object.getPrototypeOf(object));
+
+        Object.getOwnPropertyNames(object).forEach(property => properties.add(property));
+
+        return properties;
+    }
+
     /**
      * Check whether the given object is empty.
      *