trim "get classes"

ui/src/components/rects/Rect.vue

@@ -1,6 +1,6 @@
 <template>
   <rect
-    :class="classes"
+    :class="focused ? 'focus' : ''"
     :x="rectangle.left"
     :y="rectangle.top"
     :width="rectangle.width"
@@ -24,16 +24,6 @@ import { Rectangle } from "./rectangles";
 export default class Rect extends Vue {
   private focused!: boolean;
   private rectangle!: Rectangle;
-
-  private get classes(): string {
-    let result: string[] = [];
-
-    if (this.focused) {
-      result.push("focus");
-    }
-
-    return result.join(" ");
-  }
 }
 </script>