diff --git a/js/ui/layout.js b/js/ui/layout.js
index 85bbd24c2..bfe19bfcb 100644
--- a/js/ui/layout.js
+++ b/js/ui/layout.js
@@ -861,7 +861,7 @@ var LayoutManager = GObject.registerClass({
         // We can't use Params.parse here because we want to drop
         // the extra values like ancestorData.actor
         for (let prop in defaultParams) {
-            if (!params.hasOwnProperty(prop))
+            if (!Object.prototype.hasOwnProperty.call(params, prop))
                 params[prop] = ancestorData[prop];
         }
 
diff --git a/js/ui/sessionMode.js b/js/ui/sessionMode.js
index 583780111..55a422f3d 100644
--- a/js/ui/sessionMode.js
+++ b/js/ui/sessionMode.js
@@ -111,7 +111,7 @@ function _loadMode(file, info) {
     let suffix = name.indexOf('.json');
     let modeName = suffix == -1 ? name : name.slice(name, suffix);
 
-    if (_modes.hasOwnProperty(modeName))
+    if (Object.prototype.hasOwnProperty.call(_modes, modeName))
         return;
 
     let fileContent, success_, newMode;