diff --git a/src/controls/Action.qml b/src/controls/Action.qml
--- a/src/controls/Action.qml
+++ b/src/controls/Action.qml
@@ -145,28 +145,14 @@
     property list<QtObject> __children
 
     onChildrenChanged: {
-        var child;
-        for (var i in children) {
-            child = children[i];
-            if (child.hasOwnProperty("parent")) {
-                child.parent = root
-            }
-        }
+        Array.prototype.filter.call(children, child => child.hasOwnProperty("parent")).forEach(child => child.parent = root)
     }
 
     /**
      * visibleChildren: list<Action>
      * All child actions that are visible
      */
     readonly property var visibleChildren: {
-        var visible = [];
-        var child;
-        for (var i in children) {
-            child = children[i];
-            if (!child.hasOwnProperty("visible") || child.visible) {
-                visible.push(child)
-            }
-        }
-        return visible;
+        return Array.prototype.filter.call(children, child => !child.hasOwnProperty("visible") || child.visible)
     }
 }
diff --git a/src/controls/CardsLayout.qml b/src/controls/CardsLayout.qml
--- a/src/controls/CardsLayout.qml
+++ b/src/controls/CardsLayout.qml
@@ -71,8 +71,6 @@
 
     Component.onCompleted: childrenChanged()
     onChildrenChanged: {
-        for (var i = 0; i < children.length; ++i) {
-            children[i].Layout.fillHeight = true;
-        }
+        Array.prototype.forEach.call(children, child => child.Layout.fillHeight = true)
     }
 }
diff --git a/src/controls/ContextDrawer.qml b/src/controls/ContextDrawer.qml
--- a/src/controls/ContextDrawer.qml
+++ b/src/controls/ContextDrawer.qml
@@ -132,13 +132,7 @@
                 } else {
 
                     // Check if at least one action is visible
-                    var somethingVisible = false;
-                    for (var i=0; i<root.actions.length; i++) {
-                        if (root.actions[i].visible) {
-                            somethingVisible = true;
-                            break;
-                        }
-                    }
+                    var somethingVisible = root.actions.some(action => action.visible);
 
                     if (!somethingVisible) {
                         return null;
diff --git a/src/controls/FormLayout.qml b/src/controls/FormLayout.qml
--- a/src/controls/FormLayout.qml
+++ b/src/controls/FormLayout.qml
@@ -81,20 +81,10 @@
         property var knownItems: []
         property var buddies: []
         property int knownItemsImplicitWidth: {
-            var hint = 0;
-            for (var i in knownItems) {
-                hint = Math.max(hint, knownItems[i].Layout.preferredWidth > 0 ? knownItems[i].Layout.preferredWidth : knownItems[i].implicitWidth);
-            }
-            return hint;
+            return knownItems.reduce((item, widthAccumulator) => Math.max(widthAccumulator, item.Layout.preferredWidth > 0 ? item.Layout.preferredWidth : item.implicitWidth));
         }
         property int buddiesImplicitWidth: {
-            var hint = 0;
-            for (var i in buddies) {
-                if (buddies[i].visible) {
-                    hint = Math.max(hint, buddies[i].implicitWidth);
-                }
-            }
-            return hint;
+            return buddies.filter(buddy => buddy.visible).reduce((buddy, widthAccumulator) => Math.max(widthAccumulator, buddy.implicitWidth));
         }
         states: [
             State {
@@ -147,18 +137,14 @@
         Item {
             Layout.preferredWidth: {
                 var hint = 1;
-                for (var i in root.twinFormLayouts) {
-                    hint = Math.max(hint, root.twinFormLayouts[i].children[0].buddiesImplicitWidth);
-                }
+                root.twinFormLayouts.forEach(item => hint = Math.max(hint, item.children[0].buddiesImplicitWidth));
                 return hint;
             }
         }
         Item {
             Layout.preferredWidth: {
                 var hint = 1;
-                for (var i in root.twinFormLayouts) {
-                    hint = Math.max(hint, root.twinFormLayouts[i].children[0].knownItemsImplicitWidth);
-                }
+                root.twinFormLayouts.forEach(item => hint = Math.max(hint, item.children[0].knownItemsImplicitWidth));
                 return hint;
             }
         }
diff --git a/src/controls/templates/SwipeListItem.qml b/src/controls/templates/SwipeListItem.qml
--- a/src/controls/templates/SwipeListItem.qml
+++ b/src/controls/templates/SwipeListItem.qml
@@ -418,15 +418,7 @@
                 if (definitelyVisible) {
                     hasVisibleActions = true;
                 } else {
-                    var actionCount = listItem.actions.length;
-                    for (var i = 0; i < actionCount; i++) {
-                        // Assuming that visible is only false if it is explicitly false, and not just falsy
-                        if (listItem.actions[i].visible === false) {
-                            continue;
-                        }
-                        hasVisibleActions = true;
-                        break;
-                    }
+                    hasVisibleActions = listItem.actions.some(action => action.visible);
                 }
             }
 
diff --git a/src/controls/templates/private/PassiveNotification.qml b/src/controls/templates/private/PassiveNotification.qml
--- a/src/controls/templates/private/PassiveNotification.qml
+++ b/src/controls/templates/private/PassiveNotification.qml
@@ -59,9 +59,8 @@
 
         open();
 
-        for (let i = 0; i < outerLayout.children.length - 3; ++i) {
-            outerLayout.children[i].close();
-        }
+        // Skip the last three elements of this array.
+        outerLayout.children.slice(0, -3).forEach(child => child.close());
 
         let delegate = delegateComponent.createObject(outerLayout, {
             "text": message,
@@ -71,10 +70,9 @@
         });
 
         // Reorder items to have the last on top
-        let children = outerLayout.children;
-        for (let i in children) {
-            children[i].Layout.row = children.length-1-i;
-        }
+        outerLayout.children.forEach((value, index) => {
+            value.Layout.row = outerLayout.children.length-1-index;
+        });
     }
 
     Kirigami.Theme.colorSet: Kirigami.Theme.Complementary