diff --git a/src/extern/global.d.ts b/src/extern/global.d.ts
index 25aede2..c675227 100644
--- a/src/extern/global.d.ts
+++ b/src/extern/global.d.ts
@@ -1,4 +1,4 @@
-declare const qmlBase;
+declare const qmlBase: QmlObject;
 declare const notificationInvalidWindowRules: Notification;
 
 type Notification = {
diff --git a/src/extern/qt.d.ts b/src/extern/qt.d.ts
index 73c9c16..1a2b32f 100644
--- a/src/extern/qt.d.ts
+++ b/src/extern/qt.d.ts
@@ -1,6 +1,34 @@
-declare const console;
-declare const Qt;
+declare const console: {
+    log(...args: any[]);
+    assert(boolean);
+};
 
-type QRect = any;
-type QSignal = any;
-type QQmlTimer = any;
+declare const Qt: {
+    rect(x: number, y: number, width: number, height: number): QRect;
+    createQmlObject(qml: string, parent: QmlObject);
+};
+
+type QmlObject = any;
+
+type QRect = {
+    x: number;
+    y: number;
+    width: number;
+    height: number;
+    top: number;
+    bottom: number;
+    left: number;
+    right: number;
+}
+
+type QSignal = {
+    connect(handler: (...args: any[]) => void);
+    disconnect(handler: (...args: any[]) => void);
+}
+
+type QQmlTimer = {
+    interval: number;
+    triggered: QSignal;
+    restart(): void;
+    destroy(): void;
+}
diff --git a/src/layout/Desktop.ts b/src/layout/Desktop.ts
index cf71e2d..704a1ce 100644
--- a/src/layout/Desktop.ts
+++ b/src/layout/Desktop.ts
@@ -4,8 +4,8 @@ class Desktop {
     private readonly config: Desktop.Config;
     private scrollX: number;
     private dirty: boolean;
-    public clientArea: QRect;
-    public tilingArea: QRect;
+    public clientArea!: QRect;
+    public tilingArea!: QRect;
 
     constructor(desktopNumber: number, config: Desktop.Config, layoutConfig: LayoutConfig) {
         this.config = config;